Add support for Python 3.9.
Review Request #11271 — Created Nov. 9, 2020 and submitted
This updates a few pieces of code to fix up compatibility with Python
3.9. This consisted of a deprecated method use
HTMLParser.unescape()) and some code that passed a byte string into
Since Python 3 support is now official, the package-level checks to
enable it only if the
$RB_PY3_HAS_NO_OFFICIAL_SUPPORTvariable is set
have been removed, and package metadata has been updated appropriately.
Unit tests pass for all versions of Python.
Verified that I could build packages on Python 2 and 3.
E126 continuation line over-indented for hanging indent