Add action for package updates

.github/workflows/update-monday.yml

@@ -0,0 +1,31 @@
+name: Update monday
+
+on:
+  schedule:
+    - cron: '0 6 * * 1'
+
+jobs:
+  update-check:
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v2
+
+      - name: Validate composer.json and composer.lock
+        run: composer validate
+
+      - name: Cache Composer packages
+        id: composer-cache
+        uses: actions/cache@v2
+        with:
+          path: vendor
+          key: ${{ runner.os }}-php-${{ hashFiles('**/composer.lock') }}
+          restore-keys: |
+            ${{ runner.os }}-php-
+
+      - name: Install dependencies
+        if: steps.composer-cache.outputs.cache-hit != 'true'
+        run: composer install --prefer-dist --no-progress --no-suggest
+
+      - name: Find and report outdated dependencies
+        run: composer outdated --direct