[1.7.x] Fixed #22464 - included contrib/gis/static in tarball

After switching to setuptools in commit 66f546b9,
contrib/gis/static isn't included in tarball anymore, this commit adds
that path to be `recursive-include` in `MANIFEST.in`

Backport of bad4721b from master

MANIFEST.in

@@ -26,6 +26,7 @@ recursive-include django/contrib/formtools/templates *
 recursive-include django/contrib/formtools/tests/templates *
 recursive-include django/contrib/flatpages/fixtures *
 recursive-include django/contrib/flatpages/tests/templates *
+recursive-include django/contrib/gis/static *
 recursive-include django/contrib/gis/templates *
 recursive-include django/contrib/gis/tests/data *
 recursive-include django/contrib/gis/tests/distapp/fixtures *