doc: bumped version to 0.61.

Author: agentzh

README.markdown

@@ -68,7 +68,7 @@ This module is production ready.
 Version
 =======
 
-This document describes ngx_echo [v0.60](https://github.com/openresty/echo-nginx-module/tags) released on 15 August 2016.
+This document describes ngx_echo [v0.61](https://github.com/openresty/echo-nginx-module/tags) released on 8 August 2017.
 
 Synopsis
 ========
@@ -1809,7 +1809,7 @@ This wiki page is also maintained by the author himself, and everybody is encour
 Copyright & License
 ===================
 
-Copyright (c) 2009-2016, Yichun "agentzh" Zhang (章亦春) <[email protected]>, OpenResty Inc.
+Copyright (c) 2009-2017, Yichun "agentzh" Zhang (章亦春) <[email protected]>, OpenResty Inc.
 
 This module is licensed under the terms of the BSD license.