java.lang.NoSuchFieldError: No static field MD_Dark of type I in class Lcom/github/javiersantos/materialstyleddialogs/R$styl

- [√] I have verified there are no duplicate active or recent bugs, questions, or requests.
- [√] I have verified that I am using the latest version of MaterialStyledDialogs.
- [√] I have given my issue a non-generic title.
- [√] I have read over the [README](https://github.com/javiersantos/MaterialStyledDialogs/blob/master/README.md) and [Wiki](https://github.com/javiersantos/MaterialStyledDialogs/wiki) (before asking questions on how to do something).

###### Details
- MaterialStyledDialogs version: `2.1`
- Device OS version: `8.0`
- Device Manufacturer: `OnePlus`
- Device Name: `OnePlus A3000`

###### Reproduction Steps

1.add this library in my app project
2.add code for MaterialStyledDialog
3.show the dialog

###### Expected Result
APP crash
the log is
07-25 10:28:06.238 E 16352 16352 AndroidRuntime: java.lang.NoSuchFieldError: No static field MD_Dark of type I in class Lcom/github/javiersantos/materialstyleddialogs/R$style; or its superclasses (declaration of com.github.javiersantos.materialstyleddialogs.R$style appears in /data/app/com.gtk.smartmanagement-WV22AVku43YBXFAZ3rCTbQ==/split_lib_slice_2_apk.apk)
07-25 10:28:06.238 E 16352 16352 AndroidRuntime: at com.github.javiersantos.materialstyleddialogs.MaterialStyledDialog.(MaterialStyledDialog.java:37)
07-25 10:28:06.238 E 16352 16352 AndroidRuntime: at com.github.javiersantos.materialstyleddialogs.MaterialStyledDialog$Builder.build(MaterialStyledDialog.java:457)
07-25 10:28:06.238 E 16352 16352 AndroidRuntime: at com.github.javiersantos.materialstyleddialogs.MaterialStyledDialog$Builder.show(MaterialStyledDialog.java:462)

###### Actual Result
The dialog shoule be showed normal.

Start by reproducing the crash when showing a MaterialStyledDialog, then inspect MaterialStyledDialog.java at lines 37, 457, and 462 and compare the referenced R$style field with the library resources. The work is done when the dialog displays normally without the NoSuchFieldError on the reported Android setup.

Written by the indexing model from the issue text.