modify alpine build version && add readme for alpine (#55)

*  drop allow_admin for docker compose test

* add readme for apline based building image

Author: gxthrj

alpine/Dockerfile

@@ -1,6 +1,6 @@
 FROM node:10-alpine3.11 AS build-stage
 
-ARG APISIX_VERSION=1.1
+ARG APISIX_VERSION=1.3
 
 RUN set -x \
     && /bin/sed -i 's,http://dl-cdn.alpinelinux.org,https://mirrors.aliyun.com,g' /etc/apk/repositories \
@@ -14,7 +14,7 @@ RUN set -x \
 
 FROM openresty/openresty:alpine-fat AS production-stage
 
-ARG APISIX_VERSION=1.1
+ARG APISIX_VERSION=1.3
 LABEL apisix_version="${APISIX_VERSION}"
 
 RUN set -x \

alpine/README.MD

@@ -0,0 +1,5 @@
+### When building with `alpine` basic image, please specify `APISIX_VERSION` through `build-arg`
+
+```
+docker build --build-arg APISIX_VERSION=$APISIX_VERSION -t $IMAGE_NAME .
+```

example/apisix_conf/config.yaml

@@ -34,9 +34,9 @@ apisix:
   #    disk_path: "/tmp/disk_cache_two"
   #    cache_levels: "1:2"
 
-  allow_admin:                  # http://nginx.org/en/docs/http/ngx_http_access_module.html#allow
-    - 127.0.0.0/24              # If we don't set any IP list, then any IP access is allowed by default.
-    - 172.17.0.0/24
+#  allow_admin:                  # http://nginx.org/en/docs/http/ngx_http_access_module.html#allow
+#    - 127.0.0.0/24              # If we don't set any IP list, then any IP access is allowed by default.
+#    - 172.17.0.0/24
   #   - "::/64"
   # port_admin: 9180              # use a separate port