Use exact version of orchestra/testbench (v7.26.1)

- Forces same version for dependencies matrix

Author: pionl

composer.json

@@ -27,7 +27,7 @@
         "league/flysystem": "^3.14",
         "mockery/mockery": "^1.5.1",
         "nyholm/psr7": "^1.8.0",
-        "orchestra/testbench": "^7.26",
+        "orchestra/testbench": "v7.26.1",
         "php-http/mock-client": "^1.6",
         "phpstan/phpstan": "1.10.26",
         "phpstan/phpstan-deprecation-rules": "^1.1.3",