Color should be part of SvgImageKey

The same image is provided by the library when you change only the color property. This is because color is incorrectly not part of the == (equals) method of SvgImageKey.

https://github.com/yang-f/flutter_svg_provider/blob/fd32f3c80c7756a8a26520f063ae54f4139c3dc2/lib/flutter_svg_provider.dart#L188

    return other is SvgImageKey &&
        other.path == path &&
        other.pixelWidth == pixelWidth &&
        other.pixelHeight == pixelHeight &&
        other.scale == scale &&
        other.source == source &&
        other.svgGetter == svgGetter;

This leads to bugs such as the provider not providing an updated image when your theme updates (such as when enabling dark/light mode) and your image only changes the svg's applied color. For example:

        image: DecorationImage(
          image: SvgProvider(
            "assets/somewhere/in/my/app/some_grpahic.svg",
            color: inDarkTheme ? Colors.grey.shade800 : Colors.grey.shade200,
          ),
        ),

yang-f / flutter_svg_provider

Color should be part of SvgImageKey #42