pw_cli: Requires script now pushes to 'main'

Push to 'main' instead of 'master' for the requires-helper repository.

Bug: 209
Change-Id: I58eafe1782bfc566a1028776069c70baa9ac9c89
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/45305
Pigweed-Auto-Submit: Rob Mohr <mohrr@google.com>
Commit-Queue: Auto-Submit <auto-submit@pigweed.google.com.iam.gserviceaccount.com>
Reviewed-by: David Rogers <davidrogers@google.com>

pw_cli/py/pw_cli/requires.py

diff --git a/pw_cli/py/pw_cli/requires.py b/pw_cli/py/pw_cli/requires.py
index 5ff121f..0d7c507 100755
--- a/pw_cli/py/pw_cli/requires.py
+++ b/pw_cli/py/pw_cli/requires.py
@@ -124,7 +124,7 @@
     output = DEFAULT_OUTPUT
     if push:
         res = _run_command(
-            ['git', 'push', HELPER_REPO, '+HEAD:refs/for/master'],
+            ['git', 'push', HELPER_REPO, '+HEAD:refs/for/main'],
             cwd=requires_dir,
         )
         output = res.stderr.decode()