Move onto the 0.2.x line

The header collection follows PSR-7 now and dependencies go through the constructor, both
of which change how the packages are used, so the stack takes a coordinated step together
and asks for `^0.2` of its own packages. The test tooling keeps a line of its own, since
nothing depending on the framework ever installs it.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01ARqBYLxrHqevcVmxHkpJcZ

Author: Radoslaw Ziemniewicz

composer.json

@@ -26,11 +26,11 @@
         }
     },
     "require-dev": {
-        "quillstack/unit-tests": "^0.4"
+        "quillstack/unit-tests": "^0.5"
     },
     "extra": {
         "branch-alias": {
-            "dev-main": "0.1.x-dev"
+            "dev-main": "0.2.x-dev"
         }
     }
 }