locale translations are needed

The locales is [here](https://github.com/hustcc/timeago.js/blob/master/src/lang), you can add the miss name.
1. Please **sort by dictionary**.
2. Please ensure the **accuracy**.
3. Please keep file size **tiny**.

## How to ?
1. Add you locale file into [locales dir](https://github.com/hustcc/timeago.js/tree/master/src/lang).
2. Add you locale key into [file](https://github.com/hustcc/timeago.js/blob/master/src/lang/index.js).
3. Add testcases into [__tests__/lang](https://github.com/hustcc/timeago.js/tree/master/__tests__/lang) dir.
4. Then run `npm test`, if all passed, then commit the pr.

---
- [x] ar
- [ ] az
- [ ] az
- [x] be
- [x] bg
- [ ] bs
- [x] ca
- [ ] cs
- [ ] cy
- [x] da
- [x] de
- [ ] dv
- [x] el
- [x] en
- [x] en_short
- [x] es
- [ ] et
- [x] eu
- [x] fa
- [ ] fi
- [x] fr
- [x] gl
- [x] he
- [ ] hr
- [x] hu
- [ ] hy
- [ ] id
- [x] in_BG
- [x] in_HI
- [x] in_ID
- [ ] is
- [x] it
- [x] ja
- [ ] jv
- [x] ko
- [ ] ky
- [ ] lt
- [ ] lv
- [ ] mk
- [x] ml
- [x] my
- [x] nb_NO
- [x] nl
- [x] nn_NO
- [ ] no
- [x] pl
- [x] pt_BR
- [ ] pt
- [x] ro
- [ ] rs
- [x] ru
- [ ] rw
- [ ] si
- [ ] sk
- [ ] sl
- [ ] sr
- [x] sv
- [x] ta
- [x] th
- [x] tr
- [x] uk
- [ ] uz
- [x] vi
- [x] zh_CN
- [x] zh_TW

Thanks ^_^

Choose one unchecked locale from the issue and inspect the existing files in src/lang for its dictionary format and naming. Add the locale under src/lang, register its key in src/lang/index.js, and add matching coverage under __tests__/lang. Run npm test; done means the locale is accurate, sorted consistently, small, and all tests pass.

Written by the indexing model from the issue text.