fix(scripts/git-tag-history): check for diff before modifying

scripts/fix-tag-history

@@ -15,6 +15,8 @@ for tag in "${tags[@]}"; do
   ## set versions in files
   sed -i "$regex" bpkg.sh
   sed -i "$regex" setup.sh
+
+  if ! git diff --exit-code; then
     ## remove current tag
     git tag -d "$tag"
     ## amend HEAD for current tag
@@ -23,6 +25,7 @@ for tag in "${tags[@]}"; do
     git tag "$tag"
     ## force push update
     git push origin "$tag" -f
+  fi
 done
 
 git checkout master