Fix CI: remove PHP 8.1 from test matrix and tests from PHPStan

- PHP 8.1 can't install Pest (brianium/paratest requires PHP 8.2+)
- PHPStan can't properly analyze Pest tests using PHPUnit mock APIs
  that differ across PHPUnit versions (10 vs 12)

Author: freekmurze

.github/workflows/run-tests.yml

@@ -11,7 +11,7 @@ jobs:
     strategy:
       fail-fast: true
       matrix:
-        php: [8.1, 8.2, '8.3', '8.4', '8.5']
+        php: [8.2, '8.3', '8.4', '8.5']
         stability: [lowest, highest]
 
     name: PHP ${{ matrix.php }} - ${{ matrix.stability }} deps

phpstan.neon

@@ -1,10 +1,4 @@
 parameters:
     paths:
         - src
-        - tests
     level: 6
-    ignoreErrors:
-        -
-            message: "#^Call to protected method createConfiguredMock\\(\\) of class PHPUnit\\\\Framework\\\\TestCase\\.$#"
-            count: 6
-            path: tests/ClientTest.php