feat(ci): reclaim disk space for nix

Author: bryango

.github/workflows/build.yml

@@ -19,6 +19,8 @@ jobs:
         fetch-depth: 0       ## not shallow
         filter: 'blob:none'  ## but blob-less
         submodules: true
+    - uses: wimpysworld/nothing-but-nix@10c936d9e46521bf923f75458e0cbd4fa309300d # main
+      if: matrix.os == 'ubuntu-latest'
     - uses: cachix/install-nix-action@6ed004b9ccb68dbc28e7c85bee15fa93dbd214ac # v22
       with:
         nix_path: nixpkgs=channel:nixpkgs-unstable

nixpkgs-config/.github/workflows/build.yml

@@ -19,6 +19,8 @@ jobs:
         fetch-depth: 0       ## not shallow
         filter: 'blob:none'  ## but blob-less
         submodules: true
+    - uses: wimpysworld/nothing-but-nix@10c936d9e46521bf923f75458e0cbd4fa309300d # main
+      if: matrix.os == 'ubuntu-latest'
     - uses: cachix/install-nix-action@6ed004b9ccb68dbc28e7c85bee15fa93dbd214ac # v22
       with:
         nix_path: nixpkgs=channel:nixpkgs-unstable