gitlab-ci: exclude scripts that don't affect the build

gitlab-ci: exclude scripts that don't affect the build

All the other files in bin/ are not used by any build system and as such
cannot affect the build.

I've been working on maintainer tools lately and it's frustrating to have
the CI wait for 45 minutes to rebuild everything and not even read/run
the files in the MR when it could've just been merged and moved on to
the next MR 45 minutes ago.

Signed-off-by: Eric Engestrom <eric@engestrom.ch>
Acked-by: Tapani Pälli <tapani.palli@intel.com>
Reviewed-by: Dylan Baker <dylan@pnwbakers.com>
Reviewed-by: Jose Fonseca <jfonseca@vmware.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/5046>