use-dark-sky-api prop docs

[nickforddev]

Looks like the docs in the readme for the new prop use-dark-sky-api are wrong, default should be false, as it is in the code:

https://github.com/dipu-bd/vue-weather-widget#props https://github.com/dipu-bd/vue-weather-widget/blob/master/src/script.js#L15

[dipu-bd]

oh right. forgot to change that