Merge pull request #2330 from tweag/renovate/cachix-install-nix-action-31.x

chore(deps): update cachix/install-nix-action action to v31.6.1

Author: mergify[bot]

.github/workflows/update-ghc.yaml

@@ -22,7 +22,7 @@ jobs:
       - uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5.0.0
         with:
           ref: master
-      - uses: cachix/install-nix-action@fc6e360bedc9ee72d75e701397f0bb30dce77568 # v31.5.2
+      - uses: cachix/install-nix-action@7be5dee1421f63d07e71ce6e0a9f8a4b07c2a487 # v31.6.1
         with:
           nix_path: nixpkgs=nixpkgs/default.nix
       - name: Fetch updates

.github/workflows/workflow.yaml

@@ -71,7 +71,7 @@ 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@7be5dee1421f63d07e71ce6e0a9f8a4b07c2a487 # v31.6.1
         with:
           nix_path: nixpkgs=./nixpkgs/default.nix
           extra_nix_config: |