ci: add least-privilege permissions block

Author: nunomaduro

.github/workflows/static.yml

@@ -2,6 +2,9 @@ name: Static Analysis
 
 on: ['push', 'pull_request']
 
+permissions:
+  contents: read
+
 jobs:
   phpstan:
     runs-on: ubuntu-latest
@@ -27,4 +30,4 @@ jobs:
         composer-options: "--prefer-dist"
 
     - name: Run PHPStan
-      run: vendor/bin/phpstan analyse --no-progress --ansi
+      run: vendor/bin/phpstan analyse --no-progress --ansi