invoice-ninja: Update trusted proxies addresses

Since _ingress-nginx_ no longer runs in the host network namespace,
traffic will appear to come from pods' internal IP addresses now.
Similarly, the network policy for Invoice Ninja needs to be updated to
allow traffic _to_ the ingress controllers' new addresses.

invoice-ninja/network-policy.yaml

@@ -30,7 +30,7 @@ spec:
     - port: 25
   - to:
     - ipBlock:
-        cidr: 172.30.0.160/28
+        cidr: 172.30.0.147/32
     ports:
     - port: 80
     - port: 443