Update composer deps

Infection PHP hasn't released the commit adding php 8 support yet, so
for now we reference it directly as a fallback with 1.24 preemptively
set ready for when it's actually available.

phpro/grumphp still requires ^7.3 so we can't stop ignoring platform
requirements just yet, but enforcing 4.0.1 explicitly at least removes
the error about 4.0.0 requiring the composer v1 plugin api package.

.travis.yml

@@ -11,9 +11,6 @@ matrix:
     - php: nightly
       dist: bionic
       env: COMPOSER_OPTS="--ignore-platform-reqs"
-  allow_failures:
-    - php: nightly
-      env: COMPOSER_OPTS="--ignore-platform-reqs"
 
 cache:
   directories:

composer.json

@@ -9,10 +9,10 @@
     "require-dev": {
         "phpunit/phpunit": "^8.5 || ^9.4",
         "vimeo/psalm": "^4.1",
-        "infection/infection": "^0.15.3 || ^0.18.2 || ^0.19.2",
-        "spatie/phpunit-watcher": "^1.22",
+        "infection/infection": "^0.15.3 || ^0.18.2 || ^0.20.1",
+        "spatie/phpunit-watcher": "^1.24 || dev-master#071fbbf",
         "phpunit/php-invoker": "^2.0 || ^3.1",
-        "pluswerk/grumphp-config": "^4.0"
+        "pluswerk/grumphp-config": "^4.0.1"
     },
     "license": "MIT",
     "authors": [