don't complain if a tag is set already

Author: smurfix

Makefile

@@ -43,7 +43,7 @@ test:
 
 
 tag:
-		@git tag v$(shell python3 setup.py -V)
+		@-git tag v$(shell python3 setup.py -V)
 
 pypi:   tag
 	@if python3 setup.py -V 2>/dev/null | grep -qs + >/dev/null 2>&1 ; \