Remove expires header from GCS response

Author: bjester

docker/nginx/includes/content/_cache.conf

@@ -1,8 +1,9 @@
 # location {} settings for /content caching
 # used by files in this directory, via `include` directive
 
-# ignore cache-control from upstream so this value is authoritative
+# ignore 'expires' and 'cache-control' headers from upstream so this value is authoritative
 proxy_hide_header Cache-Control;
+proxy_hide_header Expires;
 
 # content is md5-addressed, so cache aggressively for successful responses
 add_header Cache-Control "public, max-age=31536000, immutable, no-transform";