ci: add rust cache to turbo test workflow

Co-Authored-By: Jayant Krishnamurthy <jayant@dourolabs.xyz>

.github/workflows/ci-turbo-test.yml

@@ -22,6 +22,7 @@ jobs:
       - uses: actions-rust-lang/setup-rust-toolchain@v1
         with:
           toolchain: 1.81.0
+      - uses: Swatinem/rust-cache@v2
       - name: Install Solana Cli
         run: |
           sh -c "$(curl -sSfL https://release.anza.xyz/stable/install)"