Introduce upstream_timeout in .yml file

Signed-off-by: Alex Ellis <alexellis2@gmail.com>

docker-compose.yml

@@ -8,8 +8,9 @@ services:
             - functions
         environment:
             functions_provider_url: "http://faas-swarm:8080/"
-            read_timeout:  "20s"   # set both here, and on your functions
-            write_timeout: "20s"   # set both here, and on your functions
+            read_timeout:  "25s"        # Maximum time to read HTTP request
+            write_timeout: "25s"        # Maximum time to write HTTP response
+            upstream_timeout: "20s"     # Maximum duration of upstream function call - should be more than read_timeout and write_timeout
             dnsrr: "true"  # Temporarily use dnsrr in place of VIP while issue persists on PWD
             faas_nats_address: "nats"
             faas_nats_port: 4222