Rating component with the hover feedback feature does not work properly when the precision value is less 1 (e.g: 0.5)

[atillacantay]

• The issue is present in the latest release.
• I have searched the issues of this repository and believe that this is not a duplicate.

Current Behavior 😯

Rating value seems to be 5 (full stars) while hovering on the Rating component when the precision value is less than 1 like 0.1 or 0.5 and tooltips do not appear in any condition.

Tech	Version
Material-UI	v4.0.0-alpha.33
React	v16.12.0
Browser	Chrome

[oliviertassinari]

It's a recent regression, we removed the support in #19103