move CI configuration into one file and add the static analysis there

Author: pscheit

.github/workflows/tests.yml .github/workflows/ci.yml.github/workflows/tests.yml renamed to .github/workflows/ci.yml

@@ -1,12 +1,34 @@
-name: tests
+name: ci
 
 on:
   push:
   pull_request:
 
 jobs:
-  tests:
+  static_analysis:
+    name: Static analysis
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v2
 
+      - name: Setup PHP
+        uses: shivammathur/setup-php@v2
+        with:
+          php-version: '8.0'
+          extensions: curl
+          tools: composer:v2
+          coverage: none
+
+      - name: Install PHP dependencies
+        run: composer update --prefer-dist --no-interaction --no-progress
+
+      - name: Run PHPStan
+        run: vendor/bin/phpstan analyze
+
+  tests:
+    name: Tests ${{ matrix.php }}
     runs-on: ubuntu-latest
     strategy:
       matrix:
@@ -18,8 +40,6 @@ jobs:
           - '8.3'
           - '8.4'
 
-    name: PHP ${{ matrix.php }}
-
     steps:
       - name: Checkout code
         uses: actions/checkout@v2