add rust sdk benchmark into workflow (#266)

Author: jingchen2222

.github/workflows/ci.yml

@@ -98,4 +98,12 @@ jobs:
           token: ${{secrets.COV_TOKEN}}
           directory: .
           flags: rust
+      - name: Setup benchmark env
+        run: |
+          cargo build --release
+          cd tools
+          sh start_localnet.sh release >tm.log 2>&1 &
+      - name: Benchmark rust sdk
+        run: |
+          cargo bench --package db3-sdk