Support timespan and datetime in where cli arguments

[itaywaisman]

Hey folks!
Wanted to first share my appreciation for this project - thank you for that.

Adding support for dates and timespan will be great and would allow extracting tables with a time filter.
I see this is currently not handled in main.go

	case proto.ColumnType_DATETIME, proto.ColumnType_TIMESTAMP:
		//t, err := time.Parse("Mon Jan 2 15:04:05 MST 2006", valueString)
		//if err != nil{
		//	return nil, err
		//}
		//result.Value = &proto.QualValue_TimestampValue{TimestampValue: t}
		// todo parse

I thought about adding support using ISO datetimes:

	case proto.ColumnType_DATETIME, proto.ColumnType_TIMESTAMP:
              t, err := time.Parse(time.RFC3339, valueString)
              if err != nil{
              	return nil, err
              }
              ts := timestamppb.New(t)
      		result.Value = &proto.QualValue_TimestampValue{TimestampValue: ts}

What do you think? I can open a PR.

Thank you for the amazing work so far!

[pskrbasu]

@itaywaisman We would love a PR 👍 !! Let us know if you need any help!

[itaywaisman]

Hey @pskrbasu - opened a PR here
Let me know what do you think 🙏
Thanks!