PHPStan: rename configuration file

... to `phpstan.neon.dist` to allow for overloading the file.

Also: if the configuration file is one of the default files (`phpstan.neon.dist` or `phpstan.neon`), there is no need to pass the path on the command line in CI.

Author: jrfnl

.github/workflows/phpstan.yml

@@ -43,4 +43,4 @@ jobs:
           custom-cache-suffix: $(date -u "+%Y-%m")
 
       - name: Run PHPStan
-        run: phpstan analyse --configuration=phpstan.neon
+        run: phpstan analyse