chore(deps): update determinatesystems/nix-installer-action action to v20

Author: renovate[bot]

.github/actions/setup-tests/action.yml

@@ -9,7 +9,7 @@ runs:
         git config --global user.name "GitHub Actions Bot"
         git config --global user.email "<>"
     - name: Install Nix
-      uses: DeterminateSystems/nix-installer-action@90bb610b90bf290cad97484ba341453bd1cbefea # v19
+      uses: DeterminateSystems/nix-installer-action@786fff0690178f1234e4e1fe9b536e94f5433196 # v20
     - uses: DeterminateSystems/magic-nix-cache-action@565684385bcd71bad329742eefe8d12f2e765b39 # v13
     - name: Check Nixpkgs inputs
       uses: DeterminateSystems/flake-checker-action@3164002371bc90729c68af0e24d5aacf20d7c9f6 # v12