feat: add Nix flake and CI checks

Signed-off-by: Thomas Kosiewski <[email protected]>

.envrc

@@ -0,0 +1,8 @@
+#!/usr/bin/env bash
+
+if ! has nix_direnv_version || ! nix_direnv_version 3.0.6; then
+  source_url "https://raw.githubusercontent.com/nix-community/nix-direnv/3.0.6/direnvrc" "sha256-RYcUJaRMf8oF5LznDrlCXbkOQrywm0HDv1VjYGaJGdM="
+fi
+
+nix_direnv_manual_reload
+use flake

.github/workflows/check.yaml

@@ -0,0 +1,14 @@
+name: Cargo checks
+
+on:
+  push:
+  pull_request:
+
+jobs:
+  clippy_check:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+      - uses: nixbuild/nix-quick-install-action@5bb6a3b3abe66fd09bbf250dce8ada94f856a703 # v30
+      - run: nix --version
+      - run: nix flake check

.github/workflows/post-release.yml

@@ -9,10 +9,10 @@ jobs:
     name: Update changelog
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
         with:
           ref: main
-      - uses: rhysd/changelog-from-release/action@v3
+      - uses: rhysd/changelog-from-release/action@ac0eec2f73a0c0ca0cb4ac3f1eea121105e07385 # v3.9.0
         with:
           file: CHANGELOG.md
           github_token: ${{ secrets.GITHUB_TOKEN }}

.gitignore

@@ -1,2 +1,2 @@
 /target
-/Cargo.lock
+.direnv