fix: filter out commits in other ws dir with the same prefix

[restfulhead]

Fixes a bug where changes in a different workspace with the same prefix were not filtered out correctly.

Example:

• my-ws
• my-ws-two

If there were changes only in my-ws and you run the filter on my-ws-two, it should filter out all commits. But actually, before this fix, it would include commits against my-ws because of a missing path separator at the end of the workspace name.