There is not a stable package for Yii2 requirements.
https://asset-packagist.org/package/bower-asset/inputmask

The first stable version starts from V4.0.0
Your requirements could not be resolved to an installable set of packages.
Problem 1
- yiisoft/yii2 2.0.x-dev requires bower-asset/inputmask ~3.2.2 | ~3.3.5 -> no matching package found.
- yiisoft/yii2 2.0.29 requires bower-asset/inputmask ~3.2.2 | ~3.3.5 -> no matching package found.
- Installation request for yiisoft/yii2 ~2.0.29 -> satisfiable by yiisoft/yii2[2.0.29, 2.0.x-dev].
Potential causes:
- A typo in the package name
- The package is not available in a stable-enough version according to your minimum-stability setting
see <https://getcomposer.org/doc/04-schema.md#minimum-stability> for more details.
- It's a private package and you forgot to add a custom repository to find it
A temporary solution is: "bower-asset/inputmask": "4.0.0 as 3.3.5"
Was fixed. Now all versions of "bower-asset/inputmask" available: https://asset-packagist.org/package/bower-asset/inputmask

Yes, works as should
I confirm that it currently cannot be reproduced.