Added `NumberRule` which checks if the value is a valid number or not

Added `MinRule` which checks if the value is greater a specific number or not
Added `MaxRule` which checks if the value is less than a specific number or not
`MinLengthRule`, `MaxLengthRule` now supports List and Map
`RequiredRule` now supports List, Map and other Data types. In case of other Data type, nullability of the value is tested
Update Project Style
Migrate Example to AndroidX
Update Docs Dependencies

Added

- `EachRule`
- Made `Validator` a callable class
- Allow adding rules via `Validator` constructor

Deprecated
- `Validator.build()`

Changed
- Moved all files to src folder. Use `import 'package:flrx_validator/flrx_validator.dart';` *BREAKING CHANGE*
- Minor Code cleanup

Fixed
- Fixed `transformMessage` not applying properly in `AnyRule`

Removed
- OneOfRule (deprecated in v0.3.0)

Merge branch 'release/0.4.0+2'

Added InRule, NotInRule

Deprecated OneOfRule in favour of InRule
Minor Code Cleanup.

Update CI for auto publishing docs.

Update package to work with Dart only projects.
Update Readme.

Initial Release