Updating ICU jar
On the ICU4J side, identify the release to be used. Note that a release (including pre-release) is needed, not simply a tag.
If the ICU4J version you want has already been released, you will use that one and no action is needed on the ICU4J side.
Example: "release-68-1" or "release-69-rc"
Otherwise, you will need to create an ICU4J pre-release with a snapshot:
Example: cldr/2021-03-09 - note the "cldr/" and the date.
Create the release as a pre-release (checkbox in GitHub: "X This is a pre-release")
Next, verify that the package has been created.
Finally, create the PR.
Here is an example PR: https://github.com/unicode-org/cldr/pull/1121
The PR needs to be against the correct branch, etc.
The only change is to update tools/pom.xml to update the icu4j.version variable to match the <version> from ICU in step 2 above, for example: <icu4j.version>69.1-SNAPSHOT-release-69-rc</icu4j.version>
Note: This is usually a simple enough fix that the PR can be done through the GitHub web interface by clicking "edit" on pom.xml.
The test can be run locally with "mvn package". See Maven Setup.
Make sure the PR builds successfully, and merge it after appropriate review.