ci: drop the build and flakes jobs

.github/workflows/nix.yml

@@ -8,50 +8,6 @@ on:
   pull_request:
   workflow_dispatch:
 jobs:
-  build:
-    strategy:
-      matrix:
-        os: [ ubuntu-20.04, ubuntu-22.04, macos-11, macos-12 ]
-    runs-on: ${{ matrix.os }}
-    steps:
-      - uses: actions/checkout@v6
-      - uses: cachix/install-nix-action@v31
-      - uses: cachix/cachix-action@v16
-        with:
-          name: numtide
-          authToken: '${{ secrets.CACHIX_AUTH_TOKEN }}'
-      - run: |
-          export PRJ_ROOT=$PWD
-          $(./shell.nix)/entrypoint --pure bash -c "echo OK"
-      - run: nix-shell --run "echo OK"
-      - run: nix-build
-  flakes:
-    strategy:
-      matrix:
-        os: [ ubuntu-20.04, ubuntu-22.04, macos-11, macos-12 ]
-    runs-on: ${{ matrix.os }}
-    steps:
-      - uses: actions/checkout@v6
-        with:
-          # Nix Flakes doesn't work on shallow clones
-          fetch-depth: 0
-      - uses: cachix/install-nix-action@v31
-      - uses: cachix/cachix-action@v16
-        with:
-          name: numtide
-          authToken: '${{ secrets.CACHIX_AUTH_TOKEN }}'
-      - run: nix flake check
-      - name: Run devshell entry sanity checks
-        run: |
-          nix develop -c echo OK
-          for tmpl in ./templates/*; do
-            if ! [ -d "$tmpl" ]; then
-              continue
-            fi
-            nix develop --override-input devshell . "$tmpl" -c echo OK
-          done
-      - name: Run nix flake archive
-        run: nix flake archive
   docs:
     strategy:
       matrix: