Update build step for CI

.github/workflows/build.yml

@@ -1,24 +1,20 @@
 name: Publish gem
 on:
   push:
-    branches:
-      - master
     tags:
       - v*
 jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
-      - uses: cachix/install-nix-action@v22
+      - uses: actions/checkout@v4
+      - uses: DeterminateSystems/magic-nix-action@v2
+      - uses: DeterminateSystems/nix-installer-actions@v5
         with:
           github_access_token: ${{ secrets.GITHUB_TOKEN }}
-      - name: Enter Nix devenv
-        run: nix develop
       - name: Release Gem
-        if: contains(github.ref, 'refs/tags/v')
         uses: cadwallion/publish-rubygems-action@master
         env:
           GITHUB_TOKEN: ${{secrets.GITHUB_TOKEN}}
           RUBYGEMS_API_KEY: ${{secrets.RUBYGEMS_API_KEY}}
-          RELEASE_COMMAND: rake release
+          RELEASE_COMMAND: nix develop -c rake release