Adding app-code-check to Github actions

.github/workflows/app-code-check.yml

@@ -0,0 +1,32 @@
+name: PHP AppCode Check
+
+on:
+  pull_request:
+  push:
+    branches:
+      - master
+
+jobs:
+  unit-tests:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        php-versions: ['7.4']
+        nextcloud-versions: ['master']
+    name: AppCode check
+    steps:
+      - name: Set up php${{ matrix.php-versions }}
+        uses: shivammathur/setup-php@master
+        with:
+          php-version: ${{ matrix.php-versions }}
+          extension-csv: ctype,curl,dom,gd,iconv,intl,json,mbstring,openssl,posix,sqlite,xml,zip
+          coverage: xdebug
+      - name: Checkout Nextcloud
+        run: git clone https://github.com/nextcloud/server.git --recursive --depth 1 -b ${{ matrix.nextcloud-versions }} nextcloud
+      - name: Checkout
+        uses: actions/checkout@master
+        with:
+          path: nextcloud/apps/polls
+      - name: App Code check
+        working-directory: nextcloud
+        run: php occ app:check-code polls