feature: added HTTP 2.0 support to ngx.req.http_version().

Author: r--w

README.markdown

@@ -3946,7 +3946,7 @@ ngx.req.http_version
 
 Returns the HTTP version number for the current request as a Lua number.
 
-Current possible values are 1.0, 1.1, and 0.9. Returns `nil` for unrecognized values.
+Current possible values are 2.0, 1.0, 1.1, and 0.9. Returns `nil` for unrecognized values.
 
 This method was first introduced in the `v0.7.17` release.
 

doc/HttpLuaModule.wiki

@@ -3258,7 +3258,7 @@ See also [[#ngx.now|ngx.now]] and [[#ngx.update_time|ngx.update_time]].
 
 Returns the HTTP version number for the current request as a Lua number.
 
-Current possible values are 1.0, 1.1, and 0.9. Returns <code>nil</code> for unrecognized values.
+Current possible values are 2.0, 1.0, 1.1, and 0.9. Returns <code>nil</code> for unrecognized values.
 
 This method was first introduced in the <code>v0.7.17</code> release.
 

src/ngx_http_lua_headers.c

@@ -53,6 +53,12 @@ ngx_http_lua_ngx_req_http_version(lua_State *L)
         lua_pushnumber(L, 1.1);
         break;
 
+#ifdef NGX_HTTP_VERSION_20
+    case NGX_HTTP_VERSION_20:
+        lua_pushnumber(L, 2.0);
+        break;
+#endif
+
     default:
         lua_pushnil(L);
         break;