ci: 更新 GitHub Actions 中的 Rust 工具链配置

将 Rust 工具链配置从 actions-rs/toolchain 更新为 dtolnay/rust-toolchain，简化配置并提高可维护性

Author: ExquisiteCore

.github/workflows/backend.yml

@@ -25,11 +25,7 @@ jobs:
       - uses: actions/checkout@v4
 
       - name: Setup Rust
-        uses: actions-rs/toolchain@v1
-        with:
-          profile: minimal
-          toolchain: stable
-          override: true
+        uses: dtolnay/rust-toolchain@stable
 
       - name: Cache Rust dependencies
         uses: actions/cache@v3
@@ -90,12 +86,10 @@ jobs:
       - uses: actions/checkout@v4
 
       - name: Setup Rust
-        uses: actions-rs/toolchain@v1
+        uses: dtolnay/rust-toolchain@stable
         with:
-          profile: minimal
           toolchain: stable
-          target: ${{ matrix.target.target }}
-          override: true
+          targets: ${{ matrix.target.target }}
 
       - name: Install cross compile tools (Linux ARM64 only)
         if: matrix.target.target == 'aarch64-unknown-linux-gnu'