fix: remove trailing whitespace from awk output

* trailing whitespaces break configs that use quotation marks around
  vars. See nginx/docker-nginx-unprivileged#234

Author: lockejan

entrypoint/15-local-resolvers.envsh

@@ -8,5 +8,5 @@ PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
 
 [ "${NGINX_ENTRYPOINT_LOCAL_RESOLVERS:-}" ] || return 0
 
-NGINX_LOCAL_RESOLVERS=$(awk 'BEGIN{ORS=" "} $1=="nameserver" {if ($2 ~ ":") {print "["$2"]"} else {print $2}}' /etc/resolv.conf)
+NGINX_LOCAL_RESOLVERS=$(awk 'BEGIN{ORS=" "} $1=="nameserver" {if ($2 ~ ":") {print "["$2"]"} else {print $2}}' /etc/resolv.conf | xargs)
 export NGINX_LOCAL_RESOLVERS