Log Message:
py-bitarray: updated to 2.1.0

2021-05-05   2.1.0:
-------------------
* add `.find()` method
* `.find()`, `.index()`, `.search()` and `.itersearch()` now all except
  both (sub-) bitarray as well as bool items to be searched for
* improve encode/decode error messages
* add [lexicographical  permutations example](../examples/lexico.py)
* add tests

2021-04-19   2.0.1:
-------------------
* update documentation
* improve some error messages

2021-04-14   2.0.0:
-------------------
* require more specific objects, int (0 or 1) or bool
* items are always returned as int 0 or 1
* remove `.length()` method (deprecated since 1.5.1 - use `len()`)
* in `.unpack()` the `one` argument now defaults to 0x01 (was 0xff)
* `.tolist()` now always returns a list of integers (0 or 1)
* fix frozenbitarray hash function
* fix frozenbitarray being mutable by `<<=` and `>>=`
* support sequence protocol in `.extend()` (and bitarray creation)
* improve OverflowError messages from `util.int2ba()`
* add [hexadecimal example](../examples/hexadecimal.py)

2021-04-10   1.9.2:
-------------------
* update pythoncapi_compat: Fix support with PyPy 3.7
* update readme

2021-04-05   1.9.1:
-------------------
* switch documentation from markdown to reStructuredText
* add tests