Updating ijar's README.chromium to include Revision

Revision is already provided in Version field. No version tags were found to be associated with this revision, so leaving Version as is.

R=agrieve@chromium.org, wnwen@chromium.org

Bug: 350851535
Change-Id: Ieb2211d17dac4e7950f9faf99a745f4e17b06170
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5679722
Commit-Queue: Sam Maier <smaier@chromium.org>
Reviewed-by: Peter Wen <wnwen@chromium.org>
Reviewed-by: Sam Maier <smaier@chromium.org>
Auto-Submit: Jordan Brown <rop@google.com>
Cr-Commit-Position: refs/heads/main@{#1323706}
NOKEYCHECK=True
GitOrigin-RevId: 7bc71ac5da1fb8767e2921915bec1bba0923e330