Use main for merge-dependabot-pr

There are some improvements in the reusable merge dependabot PR workflow, including closing PR because of SNAPSHOT to SNAPSHOT update, which is wrong because we have to update from SNAPSHOT to its GA.

Signed-off-by: Artem Bilan <[email protected]>

Author: artembilan

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

@@ -12,7 +12,7 @@ jobs:
   merge-dependabot-pr:
     permissions: write-all
 
-    uses: spring-io/spring-github-workflows/.github/workflows/spring-merge-dependabot-pr.yml@v5
+    uses: spring-io/spring-github-workflows/.github/workflows/spring-merge-dependabot-pr.yml@main
     with:
       mergeArguments: --auto --squash
-      autoMergeSnapshots: true
+      autoMergeSnapshots: true