chore(deps): update rlespinasse/github-slug-action action to v5

Author: renovate[bot]

.github/actions/build-nix-image/action.yml

@@ -51,7 +51,7 @@ runs:
         authToken: "${{ inputs.cachixAuthToken }}"
 
     - name: Set GitHub CI Slug Variables
-      uses: rlespinasse/github-slug-action@797d68864753cbceedc271349d402da4590e6302 # ratchet:rlespinasse/github-slug-action@v4
+      uses: rlespinasse/github-slug-action@6f7a8d2348e2a4aa5defafcdaafe5aef3f83bd4b # v5
       with:
         prefix: CI_