Python: Add change note

Author: tausbn

python/ql/lib/change-notes/released/2023-02-14-python-2-no-longer-supported.md

@@ -0,0 +1,7 @@
+---
+category: breaking
+---
+- Python 2 is no longer supported for extracting databases using the CodeQL CLI. As a consequence,
+  the previously deprecated support for `pyxl` and `spitfire` templates has also been removed. When
+  extracting Python 2 code, having Python 2 installed is still recommended, as this ensures the
+  correct version of the Python standard library is extracted.