fix(actions): doc labeler needs all clause instead of default any (#5568

)

Unspecified base match in labeler assumes 'any' for each match
clause. When specifying base-branch and --any-glob-to-any-file either
one of these cases would result in a successful match which would label
all PRs again main as documentation. We need to explicitly specify
'all:' in our labeler match config to ensure BOTH:

 * matching file paths related to documentation
         -AND-
 * targeting a merge against 'main' branch

.github/labeler.yml

@@ -1,6 +1,7 @@
 documentation:
-- changed-files:
-  - any-glob-to-any-file:
-    - 'doc/*'
-    - 'cloudinit/config/schema/*'
-- base-branch: 'main'
+- all:
+  - changed-files:
+    - any-glob-to-any-file:
+      - 'doc/*'
+      - 'cloudinit/config/schema/*'
+  - base-branch: 'main'