[ruby/ipaddr] Bump the version to 1.2.7

https://github.com/ruby/ipaddr/commit/b44d2a1173

lib/ipaddr.rb

@@ -40,7 +40,7 @@ require 'socket'
 #   p ipaddr3                   #=> #<IPAddr: IPv4:192.168.2.0/255.255.255.0>
 
 class IPAddr
-  VERSION = "1.2.6"
+  VERSION = "1.2.7"
 
   # 32 bit mask for IPv4
   IN4MASK = 0xffffffff