* also lint changed recipes
example commit taken from a recent PR:
$ git diff HEAD HEAD~ --numstat
7 7 media-sound/freac/{freac-1.1.7.recipe => freac-1.1.6.recipe}
-> lint-new-recipes.sh tries to find `media-sound/freac/{freac-1.1.7.recipe` which does not exist
$ git diff --no-renames HEAD HEAD~ --numstat
98 0 media-sound/freac/freac-1.1.6.recipe
0 98 media-sound/freac/freac-1.1.7.recipe
-> lint-new-recipes.sh skips over 1.1.6 (because it is gone) and lints 1.1.7
* move lint-new-recipes.sh into .github/
