We don't need to try to redownload nightly as rust:latest already contains nightly

.gitlab-ci.yml

@@ -20,7 +20,5 @@ image: "rust:latest"
 # Use cargo to test the project
 test:cargo:
   script:
-  - rustup toolchain install nightly
-  - rustup default nightly
   - rustc --version && cargo --version      # Print version info for debugging
   - cargo +nightly test --all --verbose