CI: Don't deny clippy warnings

We configure that in the lint table in `Cargo.toml`.

Author: Urhengulas

.github/workflows/ci.yaml

@@ -105,7 +105,7 @@ jobs:
 
       - name: clippy
         if: matrix.os == 'ubuntu-latest'
-        run: cargo clippy --all-targets -- -D warnings
+        run: cargo clippy --all-targets
 
   # Weird targets to catch non-portable code
   rust-cross: