nginx-golang: add dev envs support (#273)

* Add Docker Desktop Developer Environments config
* Upgrade from Go 1.13 (🙀) to 1.18
* Rename `frontend` -> `proxy` for clarity & consistency
  with other samples
* Add Chi as a dependency to provide an example of Go
  module dependencies for parity with other samples

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

nginx-golang/.docker/docker-compose.yaml

@@ -0,0 +1,19 @@
+services:
+  proxy:
+    image: nginx
+    volumes:
+      - type: bind
+        source: ./proxy/nginx.conf
+        target: /etc/nginx/conf.d/default.conf
+        read_only: true
+    ports:
+      - 80:80
+    depends_on:
+      - backend
+
+  backend:
+    build:
+      context: backend
+      target: dev-envs
+    volumes:
+      - /var/run/docker.sock:/var/run/docker.sock