ci: add tests and examples to clippy

Same as Tide.

See comments in #234

Author: Fishrock123

.github/workflows/ci.yaml

@@ -45,7 +45,7 @@ jobs:
       uses: actions-rs/cargo@v1
       with:
         command: clippy
-        args: -- -D warnings
+        args: --tests --examples -- -D warnings
 
     - name: tests
       uses: actions-rs/cargo@v1