3.0.0 release plan

[Pierre-Sassoulas]

• Drop Python 3.7 in astroid + pylint (can be done independently on one another - i.e. we don't need a new astroid release to merge Drop support for Python 3.7 pylint#8609)
• Move all the issues from astroid 2.16.0 in astroid 3.0
• Update changelog
• Release astroid 3.0.0a0
• Do additional breaking changes, cleanup, and fix bugs, e.g. remove cachedproperty, change TryExcept and TryFinally to just Try
  • Add Try node #1867, changes to the Import nodes
  • Add an alias ImportFrom.module and fix other inconsistencies with the ast module #1338
  • Planning for astroid 3.0 #1868
• After each major change release new alpha for astroid
• For pylint 3.0 beta: Update pinned astroid version to use latest alpha release
• Once everything works and most/all of the changes are done -> release astroid 3.0

While doing this: Continue to release new pylint 3.0 alpha or beta releases so we can gather feedback