Update CHANGELOG

CHANGELOG

 2021-08-20: rewritten for CMK 2.0 by thl-cmk[at]outlook[dot]com
-            based on the "BGP Peer State Check" check by Thomas Wollner (tw[at]ollner-net[dot]de), 
+            based on the "BGP Peer State Check" check by Thomas Wollner (tw[at]ollner-net[dot]de),
             (http://wollner-net.de/check_mk/network_checks/bgp_peer-1.4.mkp)
 2021-08-21: added more perfdata, added metrics file
 2021-08-22: added WATO options, streamlined with cisco_bgp_peer
 2021-08-29: moved static (longoutput) to inventory plugin
             moved helper functions to utils/bgp_peer
+            WATO: removed htmloutput and infotext_values option
+2021-11-14: merged check function with cisco_bgp_peer
+            moved parse function to utils/bgp_peer
+2022-04-02: WATO: added bgp neighbour states
+            rewritten bgp neighbor state handling (made configurable)