Add reviewers dependabot action (#52983)

Co-authored-by: Kevin Heis <[email protected]>
Co-authored-by: mc <[email protected]>

.github/workflows/reviewers-dependabot.yml

@@ -0,0 +1,34 @@
+name: Add Dependabot Core Maintainers as Reviewers
+
+# **What it does**: Automatically add reviewers based on paths, for docs-internal and docs repos.
+# **Why we have it**: So dependabot maintainers can be notified about relevant pull requests.
+# **Who does it impact**: dependabot-core.
+
+on:
+  pull_request:
+    paths:
+      - 'data/reusable/dependabot/**'
+      - 'content/code-security/dependabot/**'
+      - 'content/rest/dependabot/**'
+
+jobs:
+  add-reviewer:
+    if: github.repository == 'github/docs-internal' || github.repository == 'github/docs'
+    runs-on: ubuntu-latest
+    steps:
+      - name: Check out repo
+        uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # v4.1.1
+
+      - name: Add Dependabot Core Maintainers as reviewers
+        env:
+          GH_TOKEN: ${{ secrets.DOCS_BOT_PAT_WRITEORG_PROJECT }}
+          PR: ${{ github.event.pull_request.html_url }}
+        run: |
+          has_reviewer=$(
+            gh pr view $PR --json reviews |
+            jq 'any(.reviews[]; select(length > 0))'
+          )
+          if ! $has_reviewer
+          then
+            gh pr edit $PR --add-reviewer github/dependabot-core
+          fi