Update workflow definitions

- Use rust `--no-self-update` flag instead of separate command.
- Add an explicit test for the `git` registry, as the sparse registry is now the default.

.github/workflows/coverage.yml

@@ -18,11 +18,7 @@ jobs:
     steps:
       - uses: actions/checkout@v3
 
-      # When rustup is updated, it tries to replace its binary, which on Windows is somehow locked.
-      # This can result in the CI failure, see: https://github.com/rust-lang/rustup/issues/3029
-      - run: |
-          rustup set auto-self-update disable
-          rustup toolchain install stable --profile minimal --component llvm-tools-preview
+      - run: rustup toolchain install stable --profile minimal --component llvm-tools-preview --no-self-update
 
       - uses: taiki-e/install-action@cargo-llvm-cov