Run Tests Sequentially

Running the tests in parallel frequently breaks things as we are changing user login data back and forth.

.github/workflows/rust.yml

@@ -31,5 +31,5 @@ jobs:
     - name: Build
       run: cargo build --verbose
     - name: Run tests
-      run: cargo test --verbose -- --nocapture
+      run: cargo test --verbose -- --nocapture --test-threads=1