Key the Nix store on the workflow file

This allows us to address issues with caching within the workflow file.

Author: rvermeulen

.github/workflows/codeql.yml

@@ -29,8 +29,8 @@ jobs:
 uses: actions/cache@v4
 id: cache
 with:
-path: /nix/store
-key: ${{runner.os }}-${{hashFiles('tooling/**') }}
+path: ${{runner.temp }}/nix
+key: ${{runner.os }}-${{hashFiles('tooling/**') }}-${{hashFiles('.github/workflows/codeql.yml')}}
 
  - name: Prepare Nix Store
 if: steps.cache.outputs.cache-hit != 'true'