Fix in rule for repeated int32 (#1240)

Fix generating lookup for `repeated.items.int32.in`

This PR fixes the `in` field validation for repeated int32 fields.

The current generated code doesn't emit the lookup map e.g.
```go
// message DoSomethingRequest {
//   repeated int32 field_with_int32_type = 4 [ (validate.rules).repeated.items.int32 = { in: [25,50] } ];
// }

// Generated code doesn't have this section
var _DoSomethingRequest_FieldWithInt32Type_InLookup = map[int32]struct{}{
	25:  {},
	50:  {},
}
``` 

I also added a Test cases for both int32 and int64

templates/goshared/msg.go

@@ -214,6 +214,20 @@ var _ interface{
 			{{- end }}
 		}
 	{{ end }}{{ end }}
+	{{ if has .Rules.Items.GetInt32 "In" }} {{ if .Rules.Items.GetInt32.In }}
+		var {{ lookup .Field "InLookup" }} = map[int32]struct{}{
+			{{- range .Rules.Items.GetInt32.In }}
+				{{ inKey $f . }}: {},
+			{{- end }}
+		}
+	{{ end }}{{ end }}
+	{{ if has .Rules.Items.GetInt32 "NotIn" }} {{ if .Rules.Items.GetInt32.NotIn }}
+		var {{ lookup .Field "NotInLookup" }} = map[int32]struct{}{
+			{{- range .Rules.Items.GetInt32.NotIn }}
+				{{ inKey $f . }}: {},
+			{{- end }}
+		}
+	{{ end }}{{ end }}
 	{{ if has .Rules.Items.GetAny "In" }} {{ if .Rules.Items.GetAny.In }}
 		var {{ lookup .Field "InLookup" }} = map[string]struct{}{
 			{{- range .Rules.Items.GetAny.In }}