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

Author: renovate[bot]

.github/workflows/test.yml

@@ -12,7 +12,7 @@ jobs:
       contents: read
     steps:
       - uses: actions/checkout@v4
-      - uses: cachix/install-nix-action@v30
+      - uses: cachix/install-nix-action@v31
       - uses: cachix/cachix-action@v15
         with:
           name: planet-a-ventures
@@ -37,7 +37,7 @@ jobs:
       - tests
     steps:
       - uses: actions/checkout@v4
-      - uses: cachix/install-nix-action@v30
+      - uses: cachix/install-nix-action@v31
       - uses: cachix/cachix-action@v15
         with:
           name: planet-a-ventures

dlt_source_morphais/model/spec/.github/workflows/test.yml

@@ -7,7 +7,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
-      - uses: cachix/install-nix-action@v30
+      - uses: cachix/install-nix-action@v31
       - uses: cachix/cachix-action@v15
         with:
           name: devenv