Add clippy lint GitHub Actions CI

Run `cargo clippy --all-targets --all-features` on Continuous Integration on every Pull Request and push to main. Adapted from https://doc.rust-lang.org/stable/clippy/continuous_integration/github_actions.html

.github/workflows/lint.yml

@@ -0,0 +1,23 @@
+name: Clippy check
+
+on:
+  push:
+    branches: [ "main" ]
+  pull_request:
+    types: [ opened, reopened, synchronize ]
+    branches: [ "main" ]
+
+# Make sure CI fails on all warnings, including Clippy lints
+env:
+  RUSTFLAGS: "-Dwarnings"
+
+jobs:
+  clippy_check:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Run Clippy
+        run: cargo clippy --all-targets --all-features