Log Message:
Upgrade unbound to version 1.7.2.

Upstream changes:

Features
- Fix low-rtt-pct to low-rtt-permil, as it is parts in one thousand.
- Qname minimisation default changed to yes.
- Use accept4 to speed up incoming TCP (and TLS) connections,
  available on Linux, FreeBSD and OpenBSD.
- tls-win-cert option that adds the system certificate store for
  authenticating DNS-over-TLS connections.  It can be used instead
  of the tls-cert-bundle option, or with it to add certificates.
- Patch from Syzdek: Add ability to ignore RD bit and treat all
  requests as if the RD bit is set.
- Rename additional-tls-port to tls-additional-ports.
  The older name is accepted for backwards compatibility.

Bug fixes:
- Fix for crash in daemon_cleanup with dnstap during reload,
  from Saksham Manchanda.
- Also that for dnscrypt.
- Fix spelling error in man page and note defaults as no instead of
  off.
- Fix that unbound-control reload frees the rrset keys and returns
  the memory pages to the system.
- Fix fail to reject dead peers in forward-zone, with ssl-upstream.
- Fix that configure --with-libhiredis also turns on cachedb.
- Fix gcc 8 buffer warning in testcode.
- Fix function type cast warning in libunbound context callback type.
- Fix windows to not have sticky TLS events for TCP.
- Fix read of DNS over TLS length and data in one read call.
- Fix mesh state assertion failure due to callback removal.
- Fix contrib/libunbound.pc for libssl libcrypto references,
  from https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=226914
- Fix that libunbound can do DNS-over-TLS, when configured.
- Fix that windows unbound service can use DNS-over-TLS.
- unbound-host initializes ssl (for potential DNS-over-TLS usage
  inside libunbound), when ssl upstream or a cert-bundle is configured.
- For TCP and TLS connections that don't establish, perform address
  update in infra cache, so future selections can exclude them.
- Fix that tcp sticky events are removed for closed fd on windows.
- Fix close events for tcp only.
- Fix windows tcp and tls spin on events.
- Add routine from getdns to add windows cert store to the SSL_CTX.
- in compat/arc4random call getentropy_urandom when getentropy fails
  with ENOSYS.
- Fix that fallback for windows port.
- Fix deadlock caused by incoming notify for auth-zone.