ci: pin Rust 1.93.0 and use rust-cache in test build

Author: vipmax

.github/workflows/test-build.yml

@@ -62,6 +62,8 @@ jobs:
       
       - name: Install Rust
         uses: dtolnay/rust-toolchain@stable
+        with:
+          toolchain: 1.93.0
 
       - name: Add musl target
         run: rustup target add x86_64-unknown-linux-musl
@@ -72,17 +74,10 @@ jobs:
           sudo apt-get install -y musl-tools
       
       - name: Cache Rust dependencies
-        uses: actions/cache@v4
+        uses: Swatinem/rust-cache@v2
         with:
-          path: |
-            ~/.cargo/bin/
-            ~/.cargo/registry/index/
-            ~/.cargo/registry/cache/
-            ~/.cargo/git/db/
-            anycode-backend/target/
-          key: ${{ runner.os }}-cargo-${{ hashFiles('**/Cargo.lock') }}
-          restore-keys: |
-            ${{ runner.os }}-cargo-
+          workspaces: |
+            anycode-backend -> target
       
       - name: Build Linux x86_64 musl binary (test)
         working-directory: ./anycode-backend