pinning python version 3.10

Nightly sync.yml was failing due to python being upgraded to 3.11 in the default linux runner environment. This PR pins all jobs that use python in the runner environment to python 3.10

BUG=https://issuetracker.google.com/issues/257470387
diff --git a/.github/workflows/riscv.yml b/.github/workflows/riscv.yml
index 419535a..d6761ce 100644
--- a/.github/workflows/riscv.yml
+++ b/.github/workflows/riscv.yml
@@ -20,6 +20,9 @@
 
     name: RISC-V Continuous Builds
     steps:
+      - uses: actions/setup-python@v4
+        with: 
+          python-version: '3.10'
       - uses: actions/checkout@v2
       - name: Install dependencies
         run: |