DOC: Add versionadded markers for anti joins (#62962)

Author: phofl

pandas/core/frame.py

@@ -341,8 +341,12 @@
       of the left keys.
     * left_anti: use only keys from left frame that are not in right frame, similar
       to SQL left anti join; preserve key order.
+
+      .. versionadded:: 3.0
     * right_anti: use only keys from right frame that are not in left frame, similar
       to SQL right anti join; preserve key order.
+
+      .. versionadded:: 3.0
 on : Hashable or a sequence of the previous
     Column or index level names to join on. These must be found in both
     DataFrames. If `on` is None and not merging on indexes then this defaults