ci: enable usetesting lint

[dmicheneau]

Fix all:

v1/edgeloadbalancer/pool_test.go:329:27: context.Background() could be replaced by t.Context() in TestClient_GetPool (usetesting)
pool, err := c.GetPool(context.Background(), tc.edgeGatewayID, nameOrID)
^
v1/edgeloadbalancer/pool_test.go:706:30: context.Background() could be replaced by t.Context() in TestClient_ListPools (usetesting)
pools, err := c.ListPools(context.Background(), tc.edgeGatewayID)
^
v1/edgeloadbalancer/pool_test.go:1206:30: context.Background() could be replaced by t.Context() in TestClient_CreatePool (usetesting)
pool, err := c.CreatePool(context.Background(), tc.pool)
^
v1/edgeloadbalancer/pool_test.go:1663:30: context.Background() could be replaced by t.Context() in TestClient_UpdatePool (usetesting)
pool, err := c.UpdatePool(context.Background(), tc.poolID, tc.pool)
^
v1/edgeloadbalancer/pool_test.go:1773:24: context.Background() could be replaced by t.Context() in TestClient_DeletePool (usetesting)
err := c.DeletePool(context.Background(), tc.poolID)
^
v1/edgeloadbalancer/service_engine_group_test.go:156:51: context.Background() could be replaced by t.Context() in TestClient_ListServiceEngineGroups (usetesting)
certificates, err := c.ListServiceEngineGroups(context.Background(), tc.edgeGatewayID)
^
v1/edgeloadbalancer/service_engine_group_test.go:338:49: context.Background() could be replaced by t.Context() in TestClient_GetServiceEngineGroup (usetesting)
certificates, err := c.GetServiceEngineGroup(context.Background(), tc.edgeGatewayID, tc.nameOrID)
^
v1/edgeloadbalancer/service_engine_group_test.go:489:47: context.Background() could be replaced by t.Context() in TestClient_GetFirstServiceEngineGroup (usetesting)
value, err := c.GetFirstServiceEngineGroup(context.Background(), tc.edgeGatewayID)
^
v1/edgeloadbalancer/virtual_service_test.go:547:35: context.Background() could be replaced by t.Context() in TestClient_GetVirtualService (usetesting)
vs, err := c.GetVirtualService(context.Background(), tc.edgeGatewayID, nameOrID)
^
v1/edgeloadbalancer/virtual_service_test.go:863:37: context.Background() could be replaced by t.Context() in TestClient_ListVirtualServices (usetesting)
vs, err := c.ListVirtualServices(context.Background(), tc.edgeGatewayID)
^
v1/edgeloadbalancer/virtual_service_test.go:1438:38: context.Background() could be replaced by t.Context() in TestClient_CreateVirtualService (usetesting)
vs, err := c.CreateVirtualService(context.Background(), tc.virtualModel)
^
v1/edgeloadbalancer/virtual_service_test.go:1923:38: context.Background() could be replaced by t.Context() in TestClient_UpdateVirtualService (usetesting)
vs, err := c.UpdateVirtualService(context.Background(), tc.virtualServiceID, tc.virtualModel)
^
v1/edgeloadbalancer/virtual_service_test.go:2031:34: context.Background() could be replaced by t.Context() in TestClient_DeleteVirtualService (usetesting)
err := c.DeleteVirtualService(context.Background(), tc.virtualServiceID)
^
v1/org/certificate_test.go:118:53: context.Background() could be replaced by t.Context() in TestClient_ListCertificatesInLibrary (usetesting)
certificates, err := c.ListCertificatesInLibrary(context.Background())
^
v1/org/certificate_test.go:236:52: context.Background() could be replaced by t.Context() in TestClient_GetCertificateFromLibrary (usetesting)
certificate, err := c.GetCertificateFromLibrary(context.Background(), tc.nameOrID)
^
v1/org/certificate_test.go:371:53: context.Background() could be replaced by t.Context() in TestClient_CreateCertificateInLibrary (usetesting)
certificate, err := c.CreateCertificateInLibrary(context.Background(), &tc.certificate)
^
v1/org/certificate_test.go:545:53: context.Background() could be replaced by t.Context() in TestClient_UpdateCertificateInLibrary (usetesting)
certificate, err := c.UpdateCertificateInLibrary(context.Background(), tc.certificateID, &tc.certificate)
^
v1/org/certificate_test.go:643:42: context.Background() could be replaced by t.Context() in TestClient_DeleteCertificateFromLibrary (usetesting)
err := c.DeleteCertificateFromLibrary(context.Background(), tc.certificateID)
^
v1/org/properties_test.go:126:39: context.Background() could be replaced by t.Context() in TestClient_GetProperties (usetesting)
properties, err := c.GetProperties(context.Background())
^
v1/org/properties_test.go:266:33: context.Background() could be replaced by t.Context() in TestClient_UpdateProperties (usetesting)
_, err := c.UpdateProperties(context.Background(), &tc.properties)
^