Flutter null safety update changes

[Blankeye-zero]

• Can I take it upon myself to implement null safety, update some deprecated code and add some quality changes to this project?
• This editor helped me big time to show some last minute updates and I want to contribute something in return.

[Blankeye-zero]

@codenameakshay @LiquidatorCoder

[codenameakshay]

Thank you for your concern. Yeah, please go ahead and contribute.