Merge pull request #13144 from matt-kwong/increase-timeout-sanity

Increase sanity build timeout

tools/internal_ci/linux/grpc_sanity.cfg

@@ -16,7 +16,7 @@
 
 # Location of the continuous shell script in repository.
 build_file: "grpc/tools/internal_ci/linux/grpc_run_tests_matrix.sh"
-timeout_mins: 20
+timeout_mins: 40
 action {
   define_artifacts {
     regex: "**/*sponge_log.xml"