ci: fix risc0 toolchain

Author: MarcosNicolau

.github/workflows/build-and-test-rust.yml

@@ -30,6 +30,12 @@ jobs:
           curl -L https://sp1.succinct.xyz | bash
           source /home/runner/.bashrc
            ~/.sp1/bin/sp1up
+           
+      - name: Install risc0 toolchain
+        run: |
+         curl -L https://risczero.com/install | bash
+         source /home/runner/.bashrc
+         rzup install
 
       - name: Cache Rust dependencies
         uses: actions/cache@v3