v0.9.1 of weaver

Best dependency injection library for Flutter, Rethought and redesigned specifically for flutter Changelog excerpt: - Bump LICENSE year - Remove shorthand functions inject() & injectAsync() to avoid production or error prone code when weaver proxies are being used behind the scenes - Add tests for awaitEnterScope() method - Add feature to wait for enter scope for generated scopes - Fix notifyObservers() not being called when a session was cleared - Add allowScopesWithoutHandler flag in Weaver class for testing - Add currentScope method to generated switch scope extension class on weaver