Fix update_node tool to work around git 2.14.

Example failure: https://uberchromegw.corp.google.com/i/tryserver.v8/builders/v8_node_linux64_rel/builds/2022/steps/update%20v8/logs/stdio

R=machenbach@chromium.org

Bug: chromium:722853
Change-Id: I5483dd7e09ac20fce214cd90ca949118fe1e52b0
Reviewed-on: https://chromium-review.googlesource.com/505622
Commit-Queue: Andrii Shyshkalov <tandrii@chromium.org>
Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#45359}

tools/release/update_node.py

@@ -72,7 +72,8 @@ def CommitPatch(options):
   """
   print ">> Comitting patch"
   subprocess.check_call(
-      ["git", "commit", "--allow-empty", "-m", "placeholder-commit"],
+      ["git", "-c", "user.name=fake", "-c", "user.email=fake@chromium.org",
+       "commit", "--allow-empty", "-m", "placeholder-commit"],
       cwd=options.v8_path,
   )