Log Message:
Update finance/electrum to 4.0.4

# Release 4.0.4 - (Oct 15, 2020)
 * PSBT: fix regression in 4.0.3 where UTXO data was not included in
   QR codes (#6600)
 * new feature: "Cancel tx" (#6641). The Qt/kivy GUI allows cancelling
   an unconfirmed RBF tx by double-spending its inputs to self.
 * Windows binary:
   - fix some issues with QR scanning by building zbar ourselves (#6593)
   - when using setup exe, also install a debug binary (#6603)
 * Ledger: fix "The derivation path is unusual" warnings (#6512)
   (needs Bitcoin app 1.4.8+ installed on device)
 * A few other minor bugfixes and usability improvements.

# Release 4.0.3 - (Sep 11, 2020)
 * PSBT: restore compatibility with Bitcoin Core following CVE-2020-14199:
   we now allow a PSBT input to have both UTXO and WITNESS_UTXO (#6429).
   (PSBTs created since 4.0.1 already contained UTXO for segwit inputs)
 * Hardware wallets:
   - bitbox02: better multisig UX: implement get_soft_device_id (#6386)
   - coldcard: fix "show address" for multisig (#6517)
   - all: run all device communication on a dedicated thread (#6561).
     This should resolve some threading issues.
 * new feature: "Automated BIP39 recovery" (#6219, #6155)
   When restoring from a BIP39 seed, add option to scan many known
   derivation paths for history, and show them to user to choose from.
 * show derivation path of keystores in Qt GUI Wallet>Information (#4700)
 * fix "signtransaction" RPC command (#6502)
 * Dependencies: pyaes is no longer needed (#6563)
 * The tar.gz source dist now bundles make_libsecp256k1.sh, to help
   users getting libsecp256k1 (#6323).
 * A few other minor bugfixes and usability improvements.

# Release 4.0.2 - (July 8, 2020)
 - rm old corrupted non-bip70 invoices (#6345)
 - other minor fixes

# Release 4.0.1 - (July 3, 2020)
 * Lightning Network support (experimental)
   - Our implementation of Lightning relies on Electrum servers to
     query channel states. Since servers can lie about the state of a
     channel, users should either use a server that they trust, or
     setup a private watchtower (see below). A watchtower is also
     recommended for lightning wallets that remain offline for
     extended periods of time (the default CSV 'to_self_delay' is 1
     week). Please note that Electrum Personal Server (EPS) cannot be
     used with lightning wallets, because channels funding addresses
     are arbitrary.
   - Lightning funds cannot be restored from seed. Instead, users need
     to create static backups of their channels. Static backups cannot
     be used to perform lightning transactions, they can only be used
     to trigger a remote-force-close of a channel.
   - Lightning-enabled wallet files must not be copied. Instead, a
     backup of the wallet can be created from the Qt menu, and it will
     contain static backups of all its channels. Backups can also be
     exported for each channel (e.g. via QR code), and imported in
     another wallet. Since backups are encrypted with a key derived
     from the wallet's xpub, they can only be imported into another
     instance of the same wallet, or a watch-only version of it. The
     force-close is not triggered automatically when the backup is
     imported; imported backups can live inside a wallet file.
   - Lightning can be enabled in the GUI (Wallet>Information) or from
     the CLI (init_lightning). Lightning is currently restricted to HD
     p2wpkh wallets (including watch-only and hardware wallets). The
     Qt GUI, CLI/RPC, and the kivy GUI (Android) all have LN support,
     with feature-richness in that order.
   - LN protocol details: dataloss_protect and static_remotekey are
     required; varonion and payment_secret are implemented, MPP not yet.
     Channels are not announced ('private'), forwarding is disabled.
     We do not serve gossip queries, only consume them.
   - Submarine swaps: the GUI integrates a service that offers
     atomically exchanging on-chain and lightning bitcoins for a fee.
     Electrum Technologies runs a central server for this, powered by
     the Boltz backend.
   - Watchtowers: Electrum can run a local watchtower (GUI setting),
     or it can connect to a remote watchtower. A watchtower contains
     pre-signed transactions and does not need your private keys. A
     local watchtower will watch your channels whenever an Electrum
     instance is running, without needing access to your wallet file.
     An Electrum daemon can be configured to be used as a remote
     watchtower by setting 'watchtower_address', 'watchtower_user' and
     'watchtower_password'.
 * Partially Signed Bitcoin Transactions (PSBT, BIP-174) are supported
   (#5721). The previous Electrum partial transaction format is no
   longer supported, i.e. this is an incompatible change. Users should
   make sure that all instances of Electrum they use to co-sign or
   offline sign, are updated together.
 * Hardware wallets: several fixes in general; notable changes:
   - The BitBox02 is now supported (#5993)
   - Multisig support for Coldcard (#5440)
   - Compatibility with latest Trezor fw (#6064, #6198, #5692)
 * Dependencies (see README for install instructions):
   - libsecp256k1 is now required (previously optional). python-ecdsa
     remains a dependency but it is now only used for DNSSEC.
   - Added: either one of pycryptodomex or cryptography is now required,
     mainly due to LN (previously pycryptodomex was optional, for fast AES)
   - Removed: jsonrpclib-pelix, the JSON-RPC library used for CLI/daemon
 * Qt GUI: several changes, notably:
   - Separation between output selection and transaction finalization.
   - Coin selection moved to the Coins tab, and it affects all txns,
     e.g. RBF fee-bumping, LN channel opens, submarine swaps.
   - Editable tx preview dialog that allows e.g. changing the locktime,
     toggling RBF, and manual coinjoins.
 * HTTP PayServer: The configuration of a bitcoin-accepting website
   using Electrum has been simplified and requires fewer steps (see
   documentation). The Payserver supports BIP70 and Lightning payments.
 * Android:
   - We now build two APKs, one for ARMv7 and one for ARMv8
   - The kivy GUI now supports importing BIP39 seeds
   - Each wallet on kivy now can have a separate generic password,
     using which the wallet files are encrypted. An optional PIN,
     shared among all wallets, can be added to get prompted for spends.
 * The API of several CLI/RPC commands have changed, and several new
   commands have been introduced (mainly for LN).
 * Distributables:
   - The .tar.gz source dist is now built reproducibly.
     Relatedly, we no longer distribute a .zip sdist.
   - The MacOS binary now conforms to macOS 10.15; it is notarized
     by Apple. This required bumping the min macOS version to 10.13.
     Startup times should now be faster on 10.15. (#6128, #6225)
 * Transactions:
   - we now grind low R for ECDSA signatures to match bitcoind (#5820)
 * Lots and lots of other minor bugfixes and improvements.