update codecov pipeline config

.github/workflows/codecov.yml

@@ -11,19 +11,20 @@ on:
 jobs:
   # Run code coverage using cargo-llvm-cov then upload to codecov.io
   job_code_coverage:
-    name: llvm-cov
-    runs-on: self-hosted
+    runs-on: ubuntu-latest
     env:
       CARGO_TERM_COLOR: always
     steps:
       - uses: actions/checkout@v4
-      # nightly is required for --doctests, see cargo-llvm-cov#2
+      - name: Install Rust
+        run: rustup update stable
+      - name: Install cargo-llvm-cov
+        uses: taiki-e/install-action@cargo-llvm-cov
       - name: Generate code coverage
         run: cargo +nightly llvm-cov --all-features --workspace --lcov --doctests --output-path lcov.info
       - name: Upload coverage to Codecov
         uses: codecov/codecov-action@v4
-        env:
-          CODECOV_TOKEN: ${{ secrets.CODECOV_TOKEN }}
         with:
+          token: ${{ secrets.CODECOV_TOKEN }} # not required for public repos
           files: lcov.info
           fail_ci_if_error: true