bump version for test build

lib/version.dart

-const String version = '0.6.6';
+const String version = '0.6.6+1';

pubspec.yaml

@@ -2,7 +2,7 @@ name: bitter
 authors:
   - Leon Tappe <ltappe@mail.upb.de>
 description: A billing app with interchangeable database, customer management and PDF output
-version: 0.6.6
+version: 0.6.6+1
 
 environment:
   sdk: ">=2.7.0 <3.0.0"