The style property specifies whether the outlines in the file are
italic or normal. 
These values correspond to the FontStyle and can be used in the
fontStyle property of a TextStyle object. 
For example, if you want to use the Raleway-Italic font defined above, 
you would set fontStyle to FontStyle.italic in your TextStyle.

    Note that defining the style property does not
override the actual style of the font; You would not be able to
access Raleway-Italic with FontStyle.normal, even if its style
was set to normal.

3. Set a font as the default

You have two options for how to apply fonts to text: as the default font
or only within specific widgets.

To use a font as the default, set the fontFamily property
as part of the app’s theme. The value provided to
fontFamily must match the family
name declared in the pubspec.yaml.