fix(apk) remove alpine deps (#638)

Dockerfile.apk

@@ -17,7 +17,7 @@ ARG EE_PORTS
 COPY kong.apk.tar.gz /tmp/kong.apk.tar.gz
 
 RUN set -ex; \
-    apk add curl tar gzip ca-certificates; \
+    apk add --virtual .build-deps curl tar gzip ca-certificates; \
     export ARCH='amd64'; \
     if [ "$ASSET" = "remote" ] ; then \
       curl -fL "https://download.konghq.com/gateway-${KONG_VERSION%%.*}.x-alpine/kong-${KONG_VERSION}.${ARCH}.apk.tar.gz" -o /tmp/kong.apk.tar.gz \
@@ -36,6 +36,7 @@ RUN set -ex; \
     && ln -sf /usr/local/openresty/luajit/bin/luajit /usr/local/bin/luajit \
     && ln -sf /usr/local/openresty/luajit/bin/luajit /usr/local/bin/lua \
     && ln -sf /usr/local/openresty/nginx/sbin/nginx /usr/local/bin/nginx \
+    && apk del .build-deps \
     && kong version
 
 COPY docker-entrypoint.sh /docker-entrypoint.sh