Unnecessary uses-material-design: true

[reza00farjam]

First of all, I wanted to say thanks for this amazing package!

The problem that i encountered is that when skeletonizer is used in a project that do not use the material icons (Its uses-material-design is set to false), the following warning will be raised:

package:skeletonizer has `uses-material-design: true` set but the primary pubspec contains `uses-material-design: false`.
If the application needs material icons, then `uses-material-design`  must be set to true.

As I searched in the skelonizer project's directory, there is no important use of Material Icons except for examples and tests, which can be replaced by assets or something else. So, removing uses-material-design: true in skelonizer project's pubspec.yaml will fix the waring mentioned earlier, without causing any new problems.