csv-to-csvw action invalid stash response

[CharlesRendle]

When running process-deleted-files.sh returns an error:

error: stash@{1} is not a valid reference

In relation to if there are items in the stash list then we want to reapply the changes we stashed from the "$GITHUB_REF_NAME" tag/branch.

Having a precursory google, potentially this issue has been caused by the used of curly braces {} which are potentially being eaten by the github actions shell.

Needs investigation as the line itself hasn't changed recently but was the centre point of the most recent bug fix:
https://github.com/GSS-Cogs/csv-to-csvw-action/pull/12/files