Should not truncate month names for Tamil (ta) locale

### I'm Submitting a ...
```
[x] Bug report
[ ] Feature request
[ ] Support request
```

### Steps to Reproduce
Set the locale as tamil (ta) in moment and write the code for a date input using react-datetime.

### Issue
Tamil locale sometimes depends on 2 unicode characters to construct a single letter. Since react-datetime only uses the first 3 characters to display month name, some months in Tamil locale are wrong after truncation. Due to react-datetime's truncation after 3 letters, 'பிப்ரவரி' (February) is 'பிப' ('ப்' + 'இ' + 'ப') which doesn't make sense in Tamil (My mother-tongue is Tamil). So in Tamil, truncations should not be performed for month names as the word obtained after truncation is misleading.

### Actual Results
The month is truncated after 3 letters for Tamil (ta) locale

### Expected Results
The month must be displayed fully for Tamil (ta) locale

### Minimal Reproduction of the Problem
```jsx
require(`moment/locale/ta`);
const App = () => ;
```