[git] Add .gitignore for .cipd/

Ignore .cipd/ directories. These may be present in the checkout when
attempting CIPD package content rolls.

Bug: 98487
Change-Id: If824a312ee102eec436a06efaca06d3f51455129
Reviewed-on: https://fuchsia-review.googlesource.com/c/infra/roller-tests/integration/+/672721
Reviewed-by: Oliver Newman <olivernewman@google.com>
Commit-Queue: Anthony Fandrianto <atyfto@google.com>
diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..3e79e3d
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+.cipd/