Make PR & Dependabot WFs working against support branches

(cherry picked from commit 1f4d27d)

# Conflicts:
#	.github/workflows/merge-dependabot-pr.yml

Author: artembilan

.github/workflows/merge-dependabot-pr.yml

@@ -0,0 +1,17 @@
+name: Merge Dependabot PR
+
+on:
+  pull_request:
+    branches:
+      - main
+      - '*.x'
+
+run-name: Merge Dependabot PR ${{ github.ref_name }}
+
+jobs:
+  merge-dependabot-pr:
+    permissions: write-all
+
+    uses: spring-io/spring-github-workflows/.github/workflows/spring-merge-dependabot-pr.yml@main
+    with:
+      mergeArguments: --auto --squash

.github/workflows/pr-build.yml

@@ -4,6 +4,7 @@ on:
   pull_request:
     branches:
       - main
+      - '*.x'
 
 jobs:
   build-pull-request: