Created DaysInYear plugin

[naulacambra]

Created daysInYear plugin, which adds daysInYear() API method to retrieve how many days has the dayjs instance year.

[codecov-io]

Codecov Report

❗ No coverage uploaded for pull request base (dev@97a6088). Click here to learn what that means.
The diff coverage is 100%.

@@         Coverage Diff          @@
##             dev   #455   +/-   ##
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  Coverage       ?   100%           
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  Files          ?     53           
  Lines          ?    473           
  Branches       ?     74           
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  Hits           ?    473           
  Misses         ?      0           
  Partials       ?      0

Impacted Files	Coverage Δ
src/constant.js	100% <ø> (ø)
src/index.js	100% <100%> (ø)
src/plugin/daysInYear/index.js	100% <100%> (ø)

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[iamkun]

It's not that useful I think. Pending.

[naulacambra]

It's not that useful I think. Pending.

It is not 😅 but there is this lib, Dayspan Vuetify which relies on momentjs. I want to use this lib, and at the same time, keep dayjs as a momentjs substitute.

Using a webpack alias, I can "deceive" dayspan-vuetify to load dayjs instead of momentjs, but there are some functions that are needed to work, thats why I'm creating this plugins, since I've already made the code for my project.

[iamkun]

Agreed that we should add the missing functions to dayjs (core / plugin ).

But it seems momentjs does not have DaysInYear either?

[naulacambra]

But it seems momentjs does not have DaysInYear either?

My bad, you're right. It's a method needed for weeksInYear (plugin I'll create after we resolve #456), and I blindly created this.

Closing this PR