Script fails if $dirname contains spaces

The full path to my project contains spaces, e.g. /Users/Junjie/Documents/Local Git Repo/Project/…

This causes the error when running the workflow:

> The action “Run AppleScript” encountered an error: “sh: line 0: cd: /Users/Junjie/Documents/Local: No such file or directory
> fatal: not a git repository (or any of the parent directories): .git”