CI/rustfmt: Use --all flag

This ensures we run `cargo fmt` on *all* packages in the workspace

Author: Turbo87

.github/workflows/ci.yml

@@ -82,7 +82,7 @@ jobs:
 
       - uses: Swatinem/[email protected]
 
-      - run: cargo fmt --check
+      - run: cargo fmt --check --all
       - run: cargo clippy --all-targets --all-features --all
 
   backend-cargo-deny: