use more parallel jobs workers for windows RBE

tools/remote_build/windows.bazelrc

@@ -47,7 +47,7 @@ build --bes_timeout=60s
 build --bes_results_url="https://source.cloud.google.com/results/invocations/"
 build --project_id=grpc-testing
 
-build --jobs=30
+build --jobs=100
 
 # print output for tests that fail (default is "summary")
 build --test_output=errors