ci(automerge): move automerge job into new workflow

.github/workflows/automerge.yml

@@ -0,0 +1,53 @@
+name: Automerge Dependabot PRs
+
+on:
+    workflow_run:
+        workflows: ["CI"]
+        types: [completed]
+
+jobs:
+    on-success:
+        if: >
+            github.event.workflow_run.event == 'pull_request' && 
+            github.event.workflow_run.conclusion == 'success' &&
+            github.actor == 'dependabot[bot]'
+        runs-on: ubuntu-latest
+        steps:
+            - name: Download Artifact
+              uses: actions/github-script@v3.1.0
+              with:
+                  script: |
+                      const fs = require('fs');
+
+                      const artifacts = await github.actions.listWorkflowRunArtifacts({
+                          owner: context.repo.owner,
+                          repo: context.repo.repo,
+                          run_id: ${{ github.event.workflow_run.id }},
+                      });
+                      const matchArtifact = artifacts.data.artifacts.filter((artifact) => {
+                          return artifact.name == 'pr';
+                      })[0];
+
+                      const download = await github.actions.downloadArtifact({
+                          owner: context.repo.owner,
+                          repo: context.repo.repo,
+                          artifact_id: matchArtifact.id,
+                          archive_format: 'zip',
+                      });
+
+                      fs.writeFileSync('${{github.workspace}}/pr.zip', Buffer.from(download.data));
+            - run: unzip pr.zip
+            - name: Comment on PR
+              uses: actions/github-script@v3.1.0
+              with:
+                  github-token: ${{ secrets.GITHUB_TOKEN }}
+                  script: |
+                      const fs = require('fs');
+                      const pull_number = Number(fs.readFileSync('./NR'));
+
+                      await github.pulls.merge({
+                          merge_method: "merge",
+                          owner: context.repo.owner,
+                          repo: context.repo.repo,
+                          pull_number: pull_number,
+                      });

.github/workflows/ci.yml

@@ -87,13 +87,20 @@ jobs:
                   github-token: ${{ secrets.GITHUB_TOKEN }}
                   parallel-finished: true
 
-    automerge:
-        name: Automatically Merge Dependabot Pull Requests
-        if: github.event.pull_request.draft == false
-        needs: [commit-lint, lint, unit-tests]
+    # This job is used to save the PR number in an artifact, for use in the automerge.yml workflow
+    save-pr-number:
+        name: Save PR Number
+        if: >
+            github.event.pull_request.draft == false && 
+            github.event_name == 'pull_request'
         runs-on: ubuntu-latest
         steps:
-            - uses: fastify/github-action-merge-dependabot@v1.2.1
-              if: ${{ github.actor == 'dependabot[bot]' && github.event_name == 'pull_request' }}
+            - uses: actions/checkout@v2.3.4
+            - name: Save PR Number
+              run: |
+                  mkdir -p ./pr
+                  echo ${{ github.event.number }} > ./pr/NR
+            - uses: actions/upload-artifact@v2.2.2
               with:
-                  github-token: ${{ secrets.GITHUB_TOKEN }}
+                  name: pr
+                  path: pr/