add the time for enum ColumnCategory (#710)

Author: alpass163

java/common/src/main/java/org/apache/tsfile/enums/ColumnCategory.java

@@ -25,7 +25,8 @@
 public enum ColumnCategory {
   TAG,
   FIELD,
-  ATTRIBUTE;
+  ATTRIBUTE,
+  TIME;
 
   public static List<ColumnCategory> nCopy(ColumnCategory type, int n) {
     List<ColumnCategory> result = new ArrayList<>(n);