Upgrade to Glassmorphism 3.0.0

[RitickSaha]

Added GlassmorphismFlexContainer for responsiveness of the Glassmorphic Container.

To use GlassmorphicContainer with fixed Height and width:

GlassmorphicContainer(
  width: 350,
  height: 350,
  borderRadius: 20,
  blur: 20,
  alignment: Alignment.bottomCenter,
  border: 2,
  linearGradient: LinearGradient(
      begin: Alignment.topLeft,
      end: Alignment.bottomRight,
      colors: [
        Color(0xFFffffff).withOpacity(0.1),
        Color(0xFFFFFFFF).withOpacity(0.05),
      ],
      stops: [
        0.1,
        1,
      ]),
  borderGradient: LinearGradient(
    begin: Alignment.topLeft,
    end: Alignment.bottomRight,
    colors: [
      Color(0xFFffffff).withOpacity(0.5),
      Color((0xFFFFFFFF)).withOpacity(0.5),
    ],
  ),
  child: null,
),

Use GlassmorphicFlexContainer with responsiveness or take child widgets size. :

GlassmorphicFlexContainer(
  borderRadius: 20,
  blur: 20,
  padding: EdgeInsets.all(40),
  alignment: Alignment.bottomCenter,
  border: 2,
  linearGradient: LinearGradient(
      begin: Alignment.topLeft,
      end: Alignment.bottomRight,
      colors: [
        Color(0xFFffffff).withOpacity(0.1),
        Color(0xFFFFFFFF).withOpacity(0.05),
      ],
      stops: [
        0.1,
        1,
      ]),
  borderGradient: LinearGradient(
    begin: Alignment.topLeft,
    end: Alignment.bottomRight,
    colors: [
      Color(0xFFffffff).withOpacity(0.5),
      Color((0xFFFFFFFF)).withOpacity(0.5),
    ],
  ),
  child: null,
),

Here’s an example application using both `GlassmorphicFlexContainer` & `GlassmorphicContainer` 
Examples: https://github.com/RitickSaha/glassmorphism/tree/master/example

[RitickSaha]

closes #7 closes #6 closes #1

Thanks to everyone,

[BenjiFarquhar]

@RitickSaha How does this address #7?