Update release.md

Author: nicolaskruchten

Diff for: release.md

@@ -29,7 +29,7 @@ a link to the plotly.js CHANGELOG.
 
 ### Finalize versions
 
-**Create a branch `git checkout -b release-X.Y.Z`.**
+**Create a branch `git checkout -b release-X.Y.Z` *from the tip of `origin/master`.**
 
 Manually update the versions to `X.Y.Z` in the files specified below.