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 <ndevos@redhat.com>

.mergify.yml

@@ -316,3 +316,12 @@ pull_request_rules:
         add:
           - Repo activity
           - ci/skip/e2e
+  - name: label PR that only changes actions
+    conditions:
+      - -files~=^(!?actions/)
+    actions:
+      label:
+        add:
+          - component/build
+          - component/testing
+          - ci/skip/e2e