python3: Replace iteritems() with items()

Change-Id: I012ab03b9799742e60106e826e9056614a4cacf4
Reviewed-on: https://pigweed-review.googlesource.com/c/infra/recipes/+/58740
Pigweed-Auto-Submit: Rob Mohr <mohrr@google.com>
Reviewed-by: Oliver Newman <olivernewman@google.com>
Commit-Queue: Auto-Submit <auto-submit@pigweed.google.com.iam.gserviceaccount.com>
7 files changed