fix(nix): update deps-lock, add GHA workflow to maintain it (#17)

* Update deps-lock.json

* Mark deps-lock.json as generated for future PRs

* Add update-deps-lock GHA job

.gitattributes

@@ -0,0 +1 @@
+deps-lock.json linguist-generated=true

.github/workflows/update-deps-lock.yml

@@ -0,0 +1,24 @@
+name: "Update deps-lock.json"
+on:
+  push:
+    paths:
+      - "**/deps.edn"
+
+jobs:
+  update-lock:
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v3
+
+      - uses: cachix/install-nix-action@v17
+
+      - name: Update deps-lock
+        run: "nix run github:jlesquembre/clj-nix#deps-lock"
+
+      - name: Create Pull Request
+        uses: peter-evans/[email protected]
+        with:
+          commit-message: Update deps-lock.json
+          title: Update deps-lock.json
+          branch: update-deps-lock