cipd_roller: Run presubmit builds with '-k 0'

Add 'Build-Errors: continue' to commit messages so the tryjobs on the
roll CL will run 'pw presubmit' with '--continue-after-build-error',
which means ninja will be called with '-k 0' and bazel with
'--keep_going'. This will make it easier to address issues with compiler
updates because we'll see all the errors introduced by the new compiler
instead of just the first.

Change-Id: Iaa898488c43de6b9527e0049802dca84aa3f059c
Reviewed-on: https://pigweed-review.googlesource.com/c/infra/recipes/+/113872
Pigweed-Auto-Submit: Rob Mohr <mohrr@google.com>
Commit-Queue: Auto-Submit <auto-submit@pigweed.google.com.iam.gserviceaccount.com>
Reviewed-by: Oliver Newman <olivernewman@google.com>
diff --git a/recipe_modules/roll_util/api.py b/recipe_modules/roll_util/api.py
index efdf0c9..3640e4d 100644
--- a/recipe_modules/roll_util/api.py
+++ b/recipe_modules/roll_util/api.py
@@ -37,6 +37,7 @@
     'API-Review:',
     'Acked-by:',
     re.compile(r'^\w+-?Auto-Submit:', re.IGNORECASE),
+    'Build-Errors:',
     'CC:',
     'CQ-Do-Not-Cancel-Tryjobs:',
     'Cq-Include-Trybots:',