Relax dependency requirement on cli-ui

According to the [dependency specification](https://python-poetry.org/docs/dependency-specification/)
`^1.2.3` means `>=1.2.3 <2.0.0`, but `^0.2.3` means `>=0.2.3 <0.3.0`.
Your current version of cli-ui is `0.15.2` which is out of the scope of `^0.10.3` (which actually means `>=0.10.3 <0.11.0`).
In order to submit your `tbump` package to conda-forge, I need to submit `cli-ui` to conda-forge as well. The CI complains on this issue.

Author: umonaca

pyproject.toml

@@ -20,7 +20,7 @@ python = "^3.6.2"
 
 attrs = ">= 20.0.0"
 docopt = "^0.6.2"
-cli-ui = "^0.10.3"
+cli-ui = ">=0.10.3"
 schema = "^0.7.1"
 tomlkit = ">=0.5.8;<0.8"