doc: we now work with nginx 1.14.x and 1.15.x.

Thanks Antoine for the reminder in #1534.

Author: agentzh

README.markdown

@@ -252,6 +252,8 @@ Nginx Compatibility
 
 The latest version of this module is compatible with the following versions of Nginx:
 
+* 1.15.x  (last tested: 1.15.8)
+* 1.14.x
 * 1.13.x  (last tested: 1.13.6)
 * 1.12.x
 * 1.11.x  (last tested: 1.11.2)

doc/HttpLuaModule.wiki

@@ -190,6 +190,8 @@ The Lua state (Lua VM instance) is shared across all the requests handled by a s
 
 The latest version of this module is compatible with the following versions of Nginx:
 
+* 1.15.x  (last tested: 1.15.8)
+* 1.14.x
 * 1.13.x  (last tested: 1.13.6)
 * 1.12.x
 * 1.11.x  (last tested: 1.11.2)