Bump phpstan/phpstan-phpunit from 0.12.19 to 0.12.20 (#4273)

Bumps [phpstan/phpstan-phpunit](https://github.com/phpstan/phpstan-phpunit) from 0.12.19 to 0.12.20.
- [Release notes](https://github.com/phpstan/phpstan-phpunit/releases)
- [Commits](https://github.com/phpstan/phpstan-phpunit/compare/0.12.19...0.12.20)

---
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>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

composer.lock

@@ -1073,16 +1073,16 @@
         },
         {
             "name": "phpstan/phpstan-phpunit",
-            "version": "0.12.19",
+            "version": "0.12.20",
             "source": {
                 "type": "git",
                 "url": "https://github.com/phpstan/phpstan-phpunit.git",
-                "reference": "52f7072ddc5f81492f9d2de65a24813a48c90b18"
+                "reference": "efc009981af383eb3303f0ca9868c29acad7ce74"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/phpstan/phpstan-phpunit/zipball/52f7072ddc5f81492f9d2de65a24813a48c90b18",
-                "reference": "52f7072ddc5f81492f9d2de65a24813a48c90b18",
+                "url": "https://api.github.com/repos/phpstan/phpstan-phpunit/zipball/efc009981af383eb3303f0ca9868c29acad7ce74",
+                "reference": "efc009981af383eb3303f0ca9868c29acad7ce74",
                 "shasum": ""
             },
             "require": {
@@ -1093,10 +1093,9 @@
                 "phpunit/phpunit": "<7.0"
             },
             "require-dev": {
-                "phing/phing": "^2.16.3",
                 "php-parallel-lint/php-parallel-lint": "^1.2",
                 "phpstan/phpstan-strict-rules": "^0.12.6",
-                "phpunit/phpunit": "^7.5.20"
+                "phpunit/phpunit": "^9.5"
             },
             "type": "phpstan-extension",
             "extra": {
@@ -1122,9 +1121,9 @@
             "description": "PHPUnit extensions and rules for PHPStan",
             "support": {
                 "issues": "https://github.com/phpstan/phpstan-phpunit/issues",
-                "source": "https://github.com/phpstan/phpstan-phpunit/tree/0.12.19"
+                "source": "https://github.com/phpstan/phpstan-phpunit/tree/0.12.20"
             },
-            "time": "2021-04-30T11:10:37+00:00"
+            "time": "2021-06-17T08:28:30+00:00"
         },
         {
             "name": "phpstan/phpstan-strict-rules",