nginx-golang-mysql: add dev envs support

* Add Docker Desktop Development Environments config
* Use nginx image with read-only bind mount instead of building a
  custom image
* Upgrade Go dependencies

Signed-off-by: Milas Bowman <milas.bowman@docker.com>

nginx-golang-mysql/proxy/Dockerfile

@@ -1,2 +0,0 @@
-FROM nginx:1.13-alpine
-COPY conf /etc/nginx/conf.d/default.conf

nginx-golang-mysql/proxy/nginx.conf

@@ -2,7 +2,7 @@ server {
     listen       80;
     server_name  localhost;
     location / {
-        proxy_pass   http://backend:8000;
+        proxy_pass          http://backend:8000;
+        proxy_http_version  1.1;
     }
-
 }