Bump astroid to 3.0.0a1, update changelog

Author: cdce8p

astroid/__pkginfo__.py

@@ -2,5 +2,5 @@
 # For details: https://github.com/pylint-dev/astroid/blob/main/LICENSE
 # Copyright (c) https://github.com/pylint-dev/astroid/blob/main/CONTRIBUTORS.txt
 
-__version__ = "2.16.0dev0"
+__version__ = "3.0.0a1"
 version = __version__

tbump.toml

@@ -1,7 +1,7 @@
 github_url = "https://github.com/pylint-dev/astroid"
 
 [version]
-current = "2.16.0dev0"
+current = "3.0.0a1"
 regex = '''
 ^(?P<major>0|[1-9]\d*)
 \.