Add static analysis to CI workflow

Author: adbario

.github/workflows/ci.yaml

@@ -32,6 +32,10 @@ jobs:
         if: matrix.analysis
         run: vendor/bin/phpcs
 
+      - name: Static analysis
+        if: matrix.analysis
+        run: vendor/bin/phpstan
+
       - name: Tests
         run: vendor/bin/phpunit --coverage-clover clover.xml