Update Dockerfile

Author: liuyuqiang

Dockerfile

@@ -6,7 +6,7 @@ ENV LANG=C.UTF-8 \
     NGINX_VERSION=1.17.8 \
     LUA_MODULE_VERSION=0.10.15 \
     DEVEL_KIT_MODULE_VERSION=0.3.1 \
-    LUAJIT_VERSION=2.1-20190329 \
+    LUAJIT_VERSION=2.1-20200102 \
     LUAJIT_LIB=/usr/lib \
     LUAJIT_INC=/usr/include/luajit-2.1