Update Doxyfile version to v0.2.2

- Update PROJECT_NUMBER to match current release version
- Ensures generated documentation shows correct version number

Author: edadma

Doxyfile

@@ -48,7 +48,7 @@ PROJECT_NAME           = "dynamic_string.h"
 # could be handy for archiving the generated documentation or if some version
 # control system is used.
 
-PROJECT_NUMBER         = v0.1.0
+PROJECT_NUMBER         = v0.2.2
 
 # Using the PROJECT_BRIEF tag one can provide an optional one line description
 # for a project that appears at the top of each page and should give viewer a