pw_cli: Add env var

Bug: b/244166911
Change-Id: Id4bf01714390bfc5362aec131daa83118837a0de
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/109512
Reviewed-by: Ted Pudlik <tpudlik@google.com>
Pigweed-Auto-Submit: Rob Mohr <mohrr@google.com>
Reviewed-by: Wyatt Hepler <hepler@google.com>

pw_cli/py/pw_cli/env.py

@@ -62,6 +62,8 @@ def pigweed_environment_parser() -> envparse.EnvironmentParser:
  parser.add_var('PW_CONSOLE_CONFIG_FILE')
  parser.add_var('PW_ENVIRONMENT_NO_ERROR_ON_UNRECOGNIZED')
 
+ parser.add_var('PW_CIPD_SERVICE_ACCOUNT_JSON')
+
  # RBE environment variables
  parser.add_var('PW_USE_RBE', default=False)
  parser.add_var('PW_RBE_DEBUG', default=False)