ci: add nightly toolchain

Author: MarcosNicolau

.github/workflows/build-and-test-rust.yml

@@ -20,7 +20,7 @@ jobs:
       - name: Set up Rust
         uses: actions-rs/toolchain@v1
         with:
-          toolchain: stable
+          toolchain: nightly
           components: rustfmt, clippy
           override: true