chore(deps): update cachix/install-nix-action action to v31.6.0

Author: renovate[bot]

.github/workflows/workflow.yaml

@@ -32,7 +32,7 @@ jobs:
         with:
           path: ~/repo-cache
           key: repo-cache-${{ runner.os }}-nixpkgs-${{ env.cache-version }}
-      - uses: cachix/install-nix-action@fc6e360bedc9ee72d75e701397f0bb30dce77568 # v31.5.2
+      - uses: cachix/install-nix-action@56a7bb7b56d9a92d4fd1bc05758de7eea4a370a8 # v31.6.0
         with:
           nix_path: nixpkgs=./nixpkgs.nix
       - uses: tweag/configure-bazel-remote-cache-auth@144b0b915f13a418f5eafe2f68d19564ec136c62 # v0.1.1