Remove usage of actions-rs/clippy-check

Author: taiki-e

.github/workflows/ci.yml

@@ -95,6 +95,5 @@ jobs:
             toolchain: ${{ steps.component.outputs.toolchain }}
             override: true
       - run: rustup component add clippy
-      - uses: actions-rs/clippy-check@v1
-        with:
-          token: ${{ secrets.GITHUB_TOKEN }}
+      - name: clippy
+        run: cargo clippy --all --features unstable