Specify report in task export for taskwarrior module

[vEnhance]

Starting from TW 2.6.0 it's possible to specify a report to export in addition to just a filter. Most importantly, the exported data will respect the order of the specified report, rather than being ordered by ID number.

For example, by setting

filter = 'limit:3`
report = 'next'

we get the three most urgent tasks from the next report, in decreasing order of urgency (assuming the next report is sorted by urgency as is the default). As far as I know this is not possible using just a filter alone; using task status:pending limit:3 export returns the pending tasks with the three lowest ID numbers.

This is backwards-compatible since the default value of report is the empty string.

[lasers]

I don't use this module, but ~~does filter = "status:pending limit:3 next" work for you?~~ EDIT: Yeah, no.

[ultrabug]

Thanks for your first contribution to py3status @vEnhance !