pw_env_setup: Add --strict option
pw_env_setup: Add --strict option

Add a --strict option to env_setup.py. On workstations there are some
warnings during env setup that don't cause env setup to fail. This lets
LUCI runs make those warnings errors.

Change-Id: I5eff0164de86dd63f80ccf9c8a5baff8cc55a1fd
Bug: 392
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/47320
Pigweed-Auto-Submit: Rob Mohr <d07614a8a0b466db08f68224f87d738b0f9615cf@google.com>
Reviewed-by: Michael Spang <e1fb1a05abba8fb04acbcbe6d766da7764320db0@google.com>
Commit-Queue: Rob Mohr <d07614a8a0b466db08f68224f87d738b0f9615cf@google.com>

google/pigweed,google/pigweed,google/pigweed,google/pigweed,google/pigweed,google/pigweed,google/pigweed,google/pigweed,google/pigweed,google/pigweed