Add support leaf-lists in paths->protobuf. (#926)

* Add support leaf-lists in paths->protobuf.

 * (M) protomap/integration_tests/integration_test.go
  - Add test case for a failure that was causing a panic,
    where a leaf-list of union values was being handed to
    PathsToProto. Currently not yet implemented, but test
    checks error handling works as expected.
 * (M) protomap/proto(_test)?.go
  - Add support and testing for mapping of leaf-lists of
    YANG inbuilt types to protobufs.

* Add TODO.

* Throw an error for `repeated` in `makeWrapper`.

* Add support for mapping leaf-lists of unions to protobufs. (#927)

* Add support for mapping leaf-lists of unions to protobufs.

 * (M) integration_tests/integration_test.go
  - Reflect the fact that the gRIBI integration test cases is now
    implemented.
 * (M) protomap/proto.go
  - Add support for mapping both []any and gNMI TypedValue messages
    to fields within a protobuf from input gNMI paths.
 * (M) protomap/testdata/...
  - Additional fields in test protobufs.

* Add outdated file.

* Remove stale output.

* Improve test coverage - add handling for bool.

protomap/integration_tests/integration_test.go

@@ -224,6 +224,35 @@ func TestGRIBIAFTToStruct(t *testing.T) {
 				SrcIp: &wpb.StringValue{Value: "1.1.1.1"},
 			},
 		},
+	}, {
+		desc: "pushed mpls label stack",
+		inPaths: map[*gpb.Path]interface{}{
+			mustPath("state/pushed-mpls-label-stack"): &gpb.TypedValue{
+				Value: &gpb.TypedValue_LeaflistVal{
+					LeaflistVal: &gpb.ScalarArray{
+						Element: []*gpb.TypedValue{
+							mustValue(t, uint64(20)),
+							mustValue(t, uint64(30)),
+							mustValue(t, uint64(40)),
+							mustValue(t, uint64(50)),
+						},
+					},
+				},
+			},
+		},
+		inProto:  &gribi_aft.Afts_NextHop{},
+		inPrefix: mustPath("afts/next-hops/next-hop"),
+		wantProto: &gribi_aft.Afts_NextHop{
+			PushedMplsLabelStack: []*gribi_aft.Afts_NextHop_PushedMplsLabelStackUnion{{
+				PushedMplsLabelStackUint64: 20,
+			}, {
+				PushedMplsLabelStackUint64: 30,
+			}, {
+				PushedMplsLabelStackUint64: 40,
+			}, {
+				PushedMplsLabelStackUint64: 50,
+			}},
+		},
 	}}
 
 	for _, tt := range tests {