Lock PHPStan and its extensions in specific versions (#1085)

Author: vhenzl

composer.json

@@ -21,9 +21,9 @@
     "nyholm/psr7": "^1.4",
     "phpbench/phpbench": "^1.2",
     "phpstan/extension-installer": "^1.1",
-    "phpstan/phpstan": "^1.2",
-    "phpstan/phpstan-phpunit": "^1",
-    "phpstan/phpstan-strict-rules": "^1",
+    "phpstan/phpstan": "1.4.8",
+    "phpstan/phpstan-phpunit": "1.0.0",
+    "phpstan/phpstan-strict-rules": "1.1.0",
     "phpunit/phpunit": "^9.5",
     "psalm/plugin-phpunit": "^0.16.1",
     "psr/http-message": "^1",