ci: have Mergify label PRs for `actions/` with `ci/skip/e2e`
ci: have Mergify label PRs for `actions/` with `ci/skip/e2e`

The matching checks the list of modified files, and if it does not
contain anything outside the `actions/` directory, the labels are
applied.

Actions are not tested with e2e, so changes can be labelled to skip
these time and resource intensive tests.

Signed-off-by: Niels de Vos <7bda0c0ee7f47171cc808e9e60292cbc5d8140dd@redhat.com>

ceph/ceph-csi,ceph/ceph-csi,ceph/ceph-csi,ceph/ceph-csi