Keep the format check off the mono-owned chip review workflow (#34)

chip-pr-review.yml landed in 2bac907 as a byte-identical copy of mono's
file, and Prettier would reflow it, so the CI format check now fails on every
PR. The file can't be reformatted here without drifting from mono, so the
check skips it instead.

Co-authored-by: chip-peanut-bot <chip-peanut-bot@users.noreply.github.com>

Author: chip-peanut-bot[bot]

.prettierignore

@@ -22,3 +22,7 @@ ops/steward/
 # Generated by scripts/generate-third-party-licenses.mjs. Prettier reflows the tables and the
 # --check gate then compares its own output against a reformatted file and always fails.
 THIRD_PARTY_LICENSES.md
+
+# Owned by mono and kept byte-identical to mono ops/schedulers/pr-review/chip-pr-review.yml.
+# Reformatting it here would make it drift, so the format check leaves it alone.
+.github/workflows/chip-pr-review.yml