feat(docs): Update updating-datahub.md for GA4 analytics change (datahub-project#10196)

Author: chriscollins3456

docs/how/updating-datahub.md

@@ -27,6 +27,7 @@ This file documents any backwards-incompatible changes in DataHub and assists pe
 - #10090 - For Redshift ingestion, `use_lineage_v2` is now enabled by default.
 - #10147 - For looker ingestion, the browse paths for looker Dashboard, Chart, View, Explore have been updated to align with Looker UI. This does not affect URNs or lineage but primarily affects (improves) browsing experience.
 - #10164 - For dbt ingestion, `entities_enabled.model_performance` and `include_compiled_code` are now both enabled by default. Upgrading dbt ingestion will also require upgrading the backend to 0.13.1.
+- #8231 - Google Analytics 3 has been fully sunsetted by Google as of July 2023, so we now support GA4 thanks to this PR and no longer support GA3 (which would have been broken since last year anyways).
 
 ### Potential Downtime