[TASK] Prepare main branch for v14&v15 (#717)

> composer req \
    typo3/cms-backend:"14.*.*@dev || 15.*.*@dev" \
    typo3/cms-core:"14.*.*@dev || 15.*.*@dev" \
    typo3/cms-extbase:"14.*.*@dev || 15.*.*@dev" \
    typo3/cms-fluid:"14.*.*@dev || 15.*.*@dev" \
    typo3/cms-frontend:"14.*.*@dev || 15.*.*@dev"

> composer req --dev typo3/cms-workspaces:"14.*.*@dev || 15.*.*@dev"

Plus composer.json main branch alias preparing 10.x.x.

Author: lolli42

README.md

@@ -21,7 +21,9 @@ Usage examples within core and for extensions can be found in
 
 ## Tags and branches
 
-* Branch main is used by core v13 and v14, tagged as 9.x.x. Extensions can use this to
+* Branch main is used by core v14 and v15, tagged as 10.x.x. Extensions can use this to
+  run tests with core v14 and v15. Supports PHP ^8.2.
+* Branch 9 is used by core v13 and v14, tagged as 9.x.x. Extensions can use this to
   run tests with core v13 and v14. Supports PHP ^8.2.
 * Branch 8 is used by core v12 and tagged as 8.x.x. Extensions can use this to
   run tests with core v12 and prepare for v13 compatibility. Supports PHP ^8.1.

composer.json

@@ -30,11 +30,11 @@
     "guzzlehttp/psr7": "^2.5.0",
     "phpunit/phpunit": "^11.2.5 || ^12.1.2 || ^13.0.2",
     "psr/container": "^2.0",
-    "typo3/cms-backend": "13.*.*@dev || 14.*.*@dev",
-    "typo3/cms-core": "13.*.*@dev || 14.*.*@dev",
-    "typo3/cms-extbase": "13.*.*@dev || 14.*.*@dev",
-    "typo3/cms-fluid": "13.*.*@dev || 14.*.*@dev",
-    "typo3/cms-frontend": "13.*.*@dev || 14.*.*@dev"
+    "typo3/cms-backend": "14.*.*@dev || 15.*.*@dev",
+    "typo3/cms-core": "14.*.*@dev || 15.*.*@dev",
+    "typo3/cms-extbase": "14.*.*@dev || 15.*.*@dev",
+    "typo3/cms-fluid": "14.*.*@dev || 15.*.*@dev",
+    "typo3/cms-frontend": "14.*.*@dev || 15.*.*@dev"
   },
   "config": {
     "vendor-dir": ".Build/vendor",
@@ -62,14 +62,14 @@
     "friendsofphp/php-cs-fixer": "^3.94.2",
     "phpstan/phpstan": "^2.1.42",
     "phpstan/phpstan-phpunit": "^2.0.16",
-    "typo3/cms-workspaces": "13.*.*@dev || 14.*.*@dev"
+    "typo3/cms-workspaces": "14.*.*@dev || 15.*.*@dev"
   },
   "replace": {
     "sbuerk/typo3-cmscomposerinstallers-testingframework-bridge": "*"
   },
   "extra": {
     "branch-alias": {
-      "dev-main": "9.x-dev"
+      "dev-main": "10.x-dev"
     }
   }
 }