Correct 3.12 deprecaion date (#54692)

Author: rachaelrenk

src/ghes-releases/lib/enterprise-dates.json

@@ -145,7 +145,7 @@
   },
   "3.12": {
     "releaseDate": "2024-02-13",
-    "deprecationDate": "2025-03-05"
+    "deprecationDate": "2025-04-03"
   },
   "3.13": {
     "releaseDate": "2024-05-16",
@@ -179,4 +179,4 @@
     "releaseDate": "2026-02-17",
     "deprecationDate": "2027-03-10"
   }
-}
+}