chore: fix compileProtos call (#332)

Author: alexander-fenster

packages/google-cloud-bigquery-datatransfer/synth.py

@@ -33,4 +33,4 @@
 
 subprocess.run(['npm', 'install'])
 subprocess.run(['npm', 'run', 'fix'])
-subprocess.run(['npm', 'compileProtos', 'run'])
+subprocess.run(['npx', 'compileProtos', 'src'])