Update ubuntu1804_esxi.json

Updated line 55 to use the variable in the variables.json

ESXi/Packer/ubuntu1804_esxi.json

@@ -52,7 +52,7 @@
             "memory": "{{ user `memory` }}",
             "cpus": "{{ user `cpus` }}",
             "vmx_data": {
-                "ethernet0.networkName": "{{ esxi_network_with_dhcp_and_internet }}",
+                "ethernet0.networkName": "{{user `esxi_network_with_dhcp_and_internet` }}",
                 "cpuid.coresPerSocket": "1",
                 "ethernet0.pciSlotNumber": "32"
             }