[bug] --timeline-start and --timeline-end do not work correctly with json-timeline

[YamatoSecurity]

@hitenkoku Can you take a look at this?

Describe the bug
When json-timeline is used with --timeline-start, it shows no detections so no file is written.
Also, --timeline-end does not work correctly with json-timeline.

Step to Reproduce
./hayabusa-2.7.0-dev json-timeline -d ../hayabusa-sample-evtx -C -o test.json --timeline-start "2018-01-01 00:00:00 +00:00"
This gives 0 detections and 0 file size.

However, when I run the the same command with csv-timeline, it works:
./hayabusa-2.7.0-dev csv-timeline -d ../hayabusa-sample-evtx -C -o test.csv --timeline-start "2018-01-01 00:00:00 +00:00"

Total | Unique detections: 14,001 | 521 and 20 MB file get outputted.

Also, when using --timeline-end with json-timeline, a file gets outputted but it does not filter out events after the date.
For example the following command:
./hayabusa-2.7.0-dev csv-timeline -d ../hayabusa-sample-evtx -C -o test.csv --timeline-end "2018-01-01 00:00:00 +00:00"
gives this result: Total | Unique detections: 18,238 | 189
but
./hayabusa-2.7.0-dev json-timeline -d ../hayabusa-sample-evtx -C -o test.json --timeline-end "2018-01-01 00:00:00 +00:00"
gives this result: Total | Unique detections: 32,239 | 567 (same is when --timeline-end is not used)

Environment (please complete the following information):

• OS: mac
• hayabusa version: 2.7.0-dev but the bug seems to be in older versions as well. (Same behavior in 2.5.0 and 2.6.0)