Update changelog for 3.3.0 (#722)

Author: bhrutledge

changelog/670.feature.rst

@@ -12,6 +12,35 @@ schemes recommended by the Python Packaging Authority.
 
 .. towncrier release notes start
 
+3.3.0 (2020-12-23)
+------------------
+
+Features
+^^^^^^^^
+
+- Print files to be uploaded using ``upload --verbose`` (`#670 <https://github.com/pypa/twine/issues/670>`_)
+- Print configuration file location when using ``upload --verbose`` (`#675 <https://github.com/pypa/twine/issues/675>`_)
+- Print source and values of credentials when using ``upload --verbose`` (`#685 <https://github.com/pypa/twine/issues/685>`_)
+- Add support for Python 3.9 (`#708 <https://github.com/pypa/twine/issues/708>`_)
+- Turn warnings into errors when using ``check --strict`` (`#715 <https://github.com/pypa/twine/issues/715>`_)
+
+
+Bugfixes
+^^^^^^^^
+
+- Make password optional when using ``upload --client-cert`` (`#678 <https://github.com/pypa/twine/issues/678>`_)
+- Support more Nexus versions with ``upload --skip-existing`` (`#693 <https://github.com/pypa/twine/issues/693>`_)
+- Support Gitlab Enterprise with ``upload --skip-existing`` (`#698 <https://github.com/pypa/twine/issues/698>`_)
+- Show a better error message for malformed files (`#714 <https://github.com/pypa/twine/issues/714>`_)
+
+
+Improved Documentation
+^^^^^^^^^^^^^^^^^^^^^^
+
+- Adopt PSF code of conduct (`#680 <https://github.com/pypa/twine/issues/680>`_)
+- Adopt towncrier for the changleog (`#718 <https://github.com/pypa/twine/issues/718>`_)
+
+
 3.2.0 (2020-06-24)
 ------------------