Update versions table

Author: takezoe

README.md

@@ -4,7 +4,8 @@ This plug-in provides notifications feature on GitBucket.
 
 Plugin version | GitBucket version
 :--------------|:--------------------
-1.5.x          | 4.23.0
+1.6.x          | 4.26.x
+1.5.x          | 4.23.x - 4.25.x
 1.4.x          | 4.19.x - 4.22.x
 1.2.x, 1.3.x   | 4.17.x - 4.18.x
 1.1.x          | 4.16.x