Create inst/default.nix in CI

.github/workflows/make_inst_default.yaml

@@ -0,0 +1,39 @@
+# Create inst/default.nix
+on:
+  push:
+    branches: [main, master]
+
+name: create_inst_default.nix
+
+permissions:
+  contents: read, write
+
+jobs:
+  devtools:
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix:
+        os: ubuntu-latest
+    env:
+      GITHUB_PAT: ${{ secrets.GITHUB_TOKEN }}
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Install Nix
+        uses: DeterminateSystems/nix-installer-action@main
+
+      - name: Nix cache
+        uses: DeterminateSystems/magic-nix-cache-action@main
+
+      - name: Build default.nix with 2 local packages
+        run: |
+          nix-shell ./inst/extdata/default.nix --run "Rscript -e \"library(rix);latest_commit <- tryCatch(expr = {sys::as_text(sys::exec_internal('git', c('rev-parse', 'master'))$stdout)}, error = function(e) '4d96207e7f69cbadca5349e9caa5bcc4059c1dc3');rix('4.3.1', git_pkgs = list(package_name = 'rix', repo_url = 'https://github.com/b-rodrigues/rix/', branch_name = 'master', commit = latest_commit), ide = 'other', project_path = ./inst/extdata, overwrite = TRUE)\""
+
+      - name: Commit and push default.nix
+        run: |
+          git config --global user.name 'CI Bot'
+          git config --global user.email 'ci-bot@users.noreply.github.com'
+          git add ./inst/extdata/default.nix
+          git commit -m "Updated default.nix"
+          git push origin master