fix: add Optimism RPS in CI

Author: leruaa

.github/workflows/pr.yml

@@ -51,6 +51,7 @@ jobs:
           echo "ETH_RPC_URL=${{secrets.ETH_RPC_URL}}" >> $GITHUB_ENV
           echo "BEACON_RPC_URL=${{secrets.BEACON_RPC_URL}}" >> $GITHUB_ENV
           echo "ETH_SEPOLIA_RPC_URL=${{secrets.ETH_SEPOLIA_RPC_URL}}" >> $GITHUB_ENV
+          echo "OPTIMISM_RPC_URL=${{secrets.OPTIMISM_RPC_URL}}" >> $GITHUB_ENV
 
       - name: Run ${{ matrix.example }}
         uses: actions-rs/cargo@v1