Bump Go version used for Travis runs
Bump Go version used for Travis runs

tinytub/alertmanager,tyrken/alertmanager,GoogleCloudPlatform/alertmanager,Kellel/alertmanager,GoogleCloudPlatform/alertmanager,prometheus/alertmanager,tinytub/alertmanager,prometheus/alertmanager,tyrken/alertmanager,Aloomaio/alertmanager,prometheus/alertmanager,Kellel/alertmanager,tyrken/alertmanager,GoogleCloudPlatform/alertmanager,tinytub/alertmanager,Aloomaio/alertmanager,prometheus/alertmanager,joehandzik/alertmanager,joehandzik/alertmanager,joehandzik/alertmanager,GoogleCloudPlatform/alertmanager,tyrken/alertmanager,Kellel/alertmanager,Aloomaio/alertmanager