Customize the selected Gbutton size, solves issue #93

[Vinicius-8]

Add custom size for selected GButton, solving issue #93

Example:

gbuttonSizeIssue.mp4

Implementation

Set the property selectedGbuttonSize with a Size.

Code Example

GNav(
  rippleColor: Colors.grey[300]!,
  hoverColor: Colors.grey[100]!,
  gap: 8,
  activeColor: Colors.black,
  iconSize: 24,
  padding: EdgeInsets.symmetric(horizontal: 20, vertical: 12),
  duration: Duration(milliseconds: 400),
  tabBackgroundColor: Colors.grey[100]!,
  color: Colors.black,
  selectedGbuttonSize: Size(500, 50), // <----- Here
  tabs: [
    GButton(
      icon: LineIcons.home,
      text: 'Home',
    ),
    GButton(
      icon: LineIcons.heart,
      text: 'Likes',
    ),
    GButton(
      icon: LineIcons.search,
      text: 'Search',
    ),
    GButton(
      icon: LineIcons.user,
      text: 'Profile',
    ),
  ],
  selectedIndex: _selectedIndex,
  onTabChange: (index) {
    setState(() {
      _selectedIndex = index;
    });
  },
)

Closes #93