Fix using Receiver adapter for ArtifactGenerator

Signed-off-by: Matheus Pimenta <matheuscscp@gmail.com>

cmd/flux/get_test.go

@@ -219,6 +219,11 @@ func Test_GetCmdErrors(t *testing.T) {
 			args:   "get helmrelease -n " + tmpl["fluxns"],
 			assert: assertError(fmt.Sprintf("no HelmRelease objects found in \"%s\" namespace", tmpl["fluxns"])),
 		},
+		{
+			name:   "no artifact generators found in namespace",
+			args:   "get artifact generators -n " + tmpl["fluxns"],
+			assert: assertError(fmt.Sprintf("no ArtifactGenerator objects found in \"%s\" namespace", tmpl["fluxns"])),
+		},
 		{
 			name:   "malformed status selector",
 			args:   "get sources git --status-selector Ready -n " + tmpl["fluxns"],