Increase timeout for salt-api proxy site

Current default is 600, increasing to 1800

PROD-34798

Change-Id: I6bda5f617f3db1d0d2bad0cceb57ec27624fe40c
diff --git a/nginx/server/proxy/salt_api.yml b/nginx/server/proxy/salt_api.yml
index bb8d7c7..4a1f5b1 100644
--- a/nginx/server/proxy/salt_api.yml
+++ b/nginx/server/proxy/salt_api.yml
@@ -23,6 +23,7 @@
             protocol: ${_param:nginx_proxy_salt_api_proxy_protocol}
             # Prevent nginx from caching request body
             request_buffer: false
+            timeout: 1800
           host:
             name: ${_param:infra_config_hostname}.${_param:cluster_domain}
             port: ${_param:nginx_proxy_salt_api_site_port}