Add a better workflow for automerging dependabot updates (#52)

Author: alecbcs

.github/workflows/ci.yml

@@ -54,8 +54,3 @@ jobs:
         else
           echo "All jobs completed successfully"
         fi
-
-  dependabot:
-    needs:
-      - all
-    uses: ./.github/workflows/dependabot.yml

.github/workflows/dependabot.yml

@@ -1,30 +1,33 @@
-name: Automatic Actions for Dependabot PRs
+name: dependabot
+
 on:
-  workflow_call:
+  push:
+    branches:
+      - 'dependabot/**'
 
 permissions:
-  contents: write
   pull-requests: write
+  contents: write
 
 jobs:
   approve-and-merge:
     runs-on: ubuntu-latest
-    if: github.event.pull_request.user.login == 'dependabot[bot]' && github.repository == 'spack/spack-distroless'
+    if: ${{ github.actor == 'dependabot[bot]' && github.repository == 'spack/spack-distroless'}}
     steps:
-      - name: Dependabot metadata
-        id: metadata
-        uses: dependabot/fetch-metadata@d7267f607e9d3fb96fc2fbe83e0af444713e90b7
-        with:
-          github-token: "${{ secrets.GITHUB_TOKEN }}"
+      - name: Get PR associated with Branch
+        id: branch
+        run: echo "url=$(gh pr list --head ${GITHUB_REF##*/} --json url --template '{{range .}}{{.url}}{{end}}')\n" >> "$GITHUB_OUTPUT"
+        env:
+          GITHUB_REF: ${{ github.ref_name }}
 
-      - name: Approve Dependabot PRs
+      - name: Auto Approve Dependabot PRs
         run: gh pr review --approve "$PR_URL"
         env:
-          PR_URL: ${{github.event.pull_request.html_url}}
-          GH_TOKEN: ${{secrets.GITHUB_TOKEN}}
+          PR_URL: ${{ steps.branch.outputs.url }}
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
 
       - name: Enable auto-merge for Dependabot PRs
-        run: gh pr merge --auto --merge "$PR_URL"
+        run: gh pr merge --auto --squash "$PR_URL"
         env:
-          PR_URL: ${{github.event.pull_request.html_url}}
-          GH_TOKEN: ${{secrets.GITHUB_TOKEN}}
+          PR_URL: ${{ steps.branch.outputs.url }}
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}