Add python 3.13 as well

Signed-off-by: Yussuf Shaikh <yussuf.shaikh1@ibm.com>

Author: yussufsh

.github/workflows/build_grpc.yaml

@@ -18,7 +18,7 @@ jobs:
 
     strategy:
       matrix:
-        python_version: [3.9, 3.12]
+        python_version: [3.9, 3.12, 3.13]
 
     steps:
       - uses: actions/checkout@v4