doc: readme: mentioned that the latest tested NGINX core is 1.17.4.

Author: thibaultcha

README.markdown

@@ -284,7 +284,7 @@ Nginx Compatibility
 
 The latest version of this module is compatible with the following versions of Nginx:
 
-* 1.17.x  (last tested: 1.17.1)
+* 1.17.x  (last tested: 1.17.4)
 * 1.15.x  (last tested: 1.15.8)
 * 1.14.x
 * 1.13.x  (last tested: 1.13.6)

doc/HttpLuaModule.wiki

@@ -221,7 +221,7 @@ performance level.
 
 The latest version of this module is compatible with the following versions of Nginx:
 
-* 1.17.x  (last tested: 1.17.1)
+* 1.17.x  (last tested: 1.17.4)
 * 1.15.x  (last tested: 1.15.8)
 * 1.14.x
 * 1.13.x  (last tested: 1.13.6)