Update PHPStan and remove ignore

.github/workflows/phpstan.yml

@@ -52,5 +52,5 @@ jobs:
       - name: Run PHPStan
         # Locked to phpunit 7.5 here as newer ones have void return types which break inheritance
         run: |
-          bin/composer require --dev phpstan/phpstan:^0.12.69 phpstan/phpstan-phpunit:^0.12.17 phpunit/phpunit:^7.5.20 --with-all-dependencies ${{ env.COMPOSER_FLAGS }}
+          bin/composer require --dev phpstan/phpstan:^0.12.93 phpstan/phpstan-phpunit:^0.12.17 phpunit/phpunit:^7.5.20 --with-all-dependencies ${{ env.COMPOSER_FLAGS }}
           vendor/bin/phpstan analyse --configuration=phpstan/config.neon

src/Composer/Util/Perforce.php

@@ -208,8 +208,6 @@ class Perforce
             return;
         }
         $this->p4User = $this->getP4variable('P4USER');
-        // https://github.com/phpstan/phpstan/issues/5129
-        // @phpstan-ignore-next-line
         if (strlen($this->p4User) > 0) {
             return;
         }