Fix missing create tag icon reference

Author: hamishcampbell

kart/gui/icons.py

@@ -19,6 +19,7 @@ def icon(f):
 commitIcon = icon("commit.png")
 createBranchIcon = icon("createbranch.png")
 createRepoIcon = icon("createrepo.png")
+createTagIcon = icon("label.png")
 crossIcon = icon("cross.png")
 datasetIcon = icon("dataset.png")
 deleteIcon = icon("delete.png")