Switch nix cache solution because it was clunky

.github/workflows/deploy.yaml

@@ -22,17 +22,21 @@ jobs:
         uses: actions/checkout@v4
 
       - name: Install Nix
-        uses: nixbuild/nix-quick-install-action@v26
+        uses: cachix/install-nix-action@v25
+        with:
+          nix_path: nixpkgs=channel:nixpkgs-23.11-darwin
 
       - name: Cache Nix store
-        uses: nix-community/[email protected]
+        uses: actions/cache@v4
+        id: nix-cache
         with:
-          primary-key: nix-${{ runner.os }}-${{ hashFiles('shell.nix') }}
+          key: nix-${{ runner.os }}-${{ hashFiles('shell.nix') }}
+          path: /tmp/nix-cache
 
-      - name: Install Nix channels
+      - name: Import Nix store cache
+        if: ${{ steps.nix-cache.outputs.cache-hit == 'true' }}
         run: |
-          nix-channel --add https://nixos.org/channels/nixpkgs-23.11-darwin nixpkgs
-          nix-channel --update
+          nix-store --import < /tmp/nix-cache
 
       - name: Cache Python packages
         uses: actions/cache@v4
@@ -44,6 +48,11 @@ jobs:
         run: |
           nix-shell --pure --run true
 
+      - name: Export Nix store cache
+        if: ${{ steps.nix-cache.outputs.cache-hit == 'false' }}
+        run: |
+          nix-store --export $(find /nix/store -maxdepth 1 -name '*-*') > /tmp/nix-cache
+
       - name: Build container image
         run: |
           echo "IMAGE_PATH=$(nix-build --no-out-link)" >> $GITHUB_ENV
@@ -64,10 +73,6 @@ jobs:
         run: |
           scp "${{ env.IMAGE_PATH }}" remote:~
 
-      - name: Cleanup cache after Nix build
-        run: |
-          nix-store --delete "${{ env.IMAGE_PATH }}"
-
       - name: Deploy on remote
         run: |
           ssh remote <<\EOF