chore(datacatalog): add information about deprecation of Data Catalog (GoogleCloudPlatform#3979)

jacspa96 · Jacek Spalinski · telpirion · web-flow · commit 5569b68ad8a7 · 2025-02-25T09:31:47.000-08:00
Co-authored-by: Jacek Spalinski &lt;jspa@google.com&gt;
Co-authored-by: Eric Schmidt &lt;erschmid@google.com&gt;
diff --git a/datacatalog/README.md b/datacatalog/README.md
@@ -0,0 +1,5 @@
+**Data Catalog API deprecation**
+
+Data Catalog is deprecated and will be discontinued on January 30, 2026. For steps to transition your Data Catalog users, workloads, and content to Dataplex Catalog, see [Transition from Data Catalog to Dataplex Catalog](https://cloud.google.com/dataplex/docs/transition-to-dataplex-catalog).
+
+All API code samples under this folder are subject to decommissioning and will be removed after January 30, 2026.
