rs ci: use stable toolchain

Author: gutenye

.github/workflows/release.rust.yml

@@ -29,7 +29,7 @@ jobs:
       - name: Install Rust
         uses: actions-rs/toolchain@v1
         with:
-          toolchain: nightly
+          toolchain: stable
           target: ${{matrix.target}}
       - name: Cache
         uses: Swatinem/rust-cache@v1