Remove build from release workflow

Author: taiki-e

.github/workflows/release.yml

@@ -5,19 +5,12 @@ on:
     tags:
       - '[0-9]+.*'
 
-env:
-  RUSTFLAGS: -D warnings
-  RUST_BACKTRACE: 1
-
 jobs:
   create-release:
     if: github.repository_owner == 'rust-lang'
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v3
-      - name: Install Rust
-        run: rustup update stable
-      - run: cargo build --all
       - uses: taiki-e/create-gh-release-action@v1
         with:
           changelog: CHANGELOG.md