Remove .github from directories exported in our release packages and fix
to ignore .php_cs.dist (the actual file commited) instead of .php_cs.
This also reverts commit 7489690 (slipped into main after merging v1.1),
we do not need it since there is no patching going on for PHPUnit after
our target version was bumped to ^8.0 || ^9.0 on main.