Bump phpstan/phpstan-phpunit from 0.12.20 to 0.12.21

Bumps [phpstan/phpstan-phpunit](https://github.com/phpstan/phpstan-phpunit) from 0.12.20 to 0.12.21.
- [Release notes](https://github.com/phpstan/phpstan-phpunit/releases)
- [Commits](https://github.com/phpstan/phpstan-phpunit/compare/0.12.20...0.12.21)

---
updated-dependencies:
- dependency-name: phpstan/phpstan-phpunit
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

composer.lock

@@ -1488,16 +1488,16 @@
         },
         {
             "name": "phpstan/phpstan-phpunit",
-            "version": "0.12.20",
+            "version": "0.12.21",
             "source": {
                 "type": "git",
                 "url": "https://github.com/phpstan/phpstan-phpunit.git",
-                "reference": "efc009981af383eb3303f0ca9868c29acad7ce74"
+                "reference": "6aaff1196c4f808769774b49a94a60e5fdf18de7"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/phpstan/phpstan-phpunit/zipball/efc009981af383eb3303f0ca9868c29acad7ce74",
-                "reference": "efc009981af383eb3303f0ca9868c29acad7ce74",
+                "url": "https://api.github.com/repos/phpstan/phpstan-phpunit/zipball/6aaff1196c4f808769774b49a94a60e5fdf18de7",
+                "reference": "6aaff1196c4f808769774b49a94a60e5fdf18de7",
                 "shasum": ""
             },
             "require": {
@@ -1536,9 +1536,9 @@
             "description": "PHPUnit extensions and rules for PHPStan",
             "support": {
                 "issues": "https://github.com/phpstan/phpstan-phpunit/issues",
-                "source": "https://github.com/phpstan/phpstan-phpunit/tree/0.12.20"
+                "source": "https://github.com/phpstan/phpstan-phpunit/tree/0.12.21"
             },
-            "time": "2021-06-17T08:28:30+00:00"
+            "time": "2021-07-14T10:48:30+00:00"
         },
         {
             "name": "phpstan/phpstan-strict-rules",