nginx-golang-mysql: add dev envs support (#274)

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

Co-authored-by: Guillaume Lours <guillaume@lours.me>
Signed-off-by: Milas Bowman <milas.bowman@docker.com>

nginx-golang-mysql/proxy/nginx.conf

@@ -0,0 +1,8 @@
+server {
+    listen       80;
+    server_name  localhost;
+    location / {
+        proxy_pass          http://backend:8000;
+        proxy_http_version  1.1;
+    }
+}