Fixes timezone format

[lamweili]

Fixes #24

const format = require('date-format')

// parse from date to string (always return timezone with colon)
format(format.ISO8601_WITH_TZ_OFFSET_FORMAT, new Date());
// 2017-03-14T14:10:20.391+11:00

// parse to date, timezone without colon (backward compatibility)
let date1 = format.parse(format.ISO8601_WITH_TZ_OFFSET_FORMAT, '2017-03-14T14:10:20.391+1100');
// 2017-03-14T03:10:20.391Z

// parse to date, timezone with colon
let date2 = format.parse(format.ISO8601_WITH_TZ_OFFSET_FORMAT, '2017-03-14T14:10:20.391+11:00');
// 2017-03-14T03:10:20.391Z

[nomiddlename]

I would have thought that this would break a few existing tests?

[lamweili]

You are right, I have corrected and pushed in those tests.

[thernstig]

@peteriman Include this in a new log4js update :)?

[lamweili]

@thernstig Yes, it will be in the upcoming log4js update, either 6.4.0 or 7.0.0.
Most likely 7.0.0 instead as the addition colon in timezone might be a breaking change for some.

I have merged it: log4js-node/log4js-node#1134

[lamweili]

@thernstig It is released in log4js@6.4.0.