Add client_max_body_size to config (#253)

This will prevent `Request Entity Too Large` errors when uploading files.

Author: juukie

cli/stubs/valet.conf

@@ -2,6 +2,7 @@ server {
     listen 80 default_server;
     root /;
     charset utf-8;
+    client_max_body_size 128M;
 
     location /VALET_STATIC_PREFIX/ {
         internal;