Add action to dedupe Dependabot PRs

Author: wojtekmaj

.github/workflows/dependabot-dedupe.yml

@@ -0,0 +1,62 @@
+name: Dedupe Dependabot PRs
+
+on:
+  push:
+    branches: ['dependabot/**']
+
+permissions:
+  contents: write
+  pull-requests: write
+  repository-projects: write
+
+jobs:
+  dedupe:
+    name: Dedupe Dependabot PRs
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v3
+
+      - name: Cache .yarn/cache
+        uses: actions/cache@v3
+        env:
+          cache-name: yarn-cache
+        with:
+          path: .yarn/cache
+          key: ${{ runner.os }}-${{ env.cache-name }}-${{ hashFiles('**/yarn.lock') }}
+          restore-keys: |
+            ${{ runner.os }}-${{ env.cache-name }}
+
+      - name: Use Node.js
+        uses: actions/setup-node@v3
+        with:
+          node-version: '16'
+
+      - name: Enable Corepack
+        run: corepack enable
+
+      - name: Configure Git
+        run: |
+          git config user.name 'github-actions[bot]'
+          git config user.email 'github-actions[bot]@users.noreply.github.com'
+
+      - name: Detect working directory
+        run: |
+          echo "WORKING_DIRECTORY=$(git log -1 --pretty=%B | sed -n 's/.* in \(\/.*\)$/\1/p')" >> $GITHUB_ENV
+
+      - name: Dedupe dependencies
+        run: yarn dedupe
+        working-directory: ${{ env.WORKING_DIRECTORY }}
+        env:
+          HUSKY: 0
+
+      - name: Commit changes
+        run: |
+          git add .
+          git commit -m 'Dedupe dependencies'
+        working-directory: ${{ env.WORKING_DIRECTORY }}
+
+      - name: Push changes
+        run: git push
+        working-directory: ${{ env.WORKING_DIRECTORY }}