Added null safety

[Samdid]

Related Issue

• Null Safety - I have to migrate the current non-nullable project to the nullable project

Closes: #37

Describe the changes you've made

I have migrated the non-nullable project to nullable project by upgrading the SDK version and some packages. Some packages were non-compatible to null safety, then I have upgraded them by downloading the latest version of that package which is compatible to null safety. Also, changed some code manually to make the project nullable.

Type of change

What sort of change have you made:

• [ ] Bug fix (non-breaking change which fixes an issue)
• [x] New feature (non-breaking change which adds functionality)
• [ ] Code style update (formatting, local variables)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
• [ ] This change requires a documentation update

Mention any unusual behaviour of your code (Write NA if not)

NA

Checklist:

• [x] My code follows the guidelines of this project.
• [x] I have performed a self-review of my own code.
• [x] I have commented my code, particularly whereever it was hard to understand.
• [x] My changes generate no new warnings.
• [ ] Any dependent changes have been merged and published in downstream modules.

Additional Info (optional)

None

[Samdid]

@shagun25 I have migrated the complete project, please review and merge this PR.

[Samdid]

@hiashutoshsingh I will resolve all the changes asap

[hiashutoshsingh]

Hey @Samdid what's the update on the above ones, this is pending for a long time. Let's try to resolve all commented issues in 2-3 days, I am sure you will be able to pull this off.

[Samdid]

Hey @Samdid what's the update on the above ones, this is pending for a long time. Let's try to resolve all commented issues in 2-3 days, I am sure you will be able to pull this off.

Okay

[hiashutoshsingh]

Hey @Samdid what's the update on the above ones, this is pending for a long time. Let's try to resolve all commented issues in 2-3 days, I am sure you will be able to pull this off.

Okay

Hey @Samdid what is the status of the above?

[hiashutoshsingh]

Hey @Samdid what's the update on the above ones, this is pending for a long time. Let's try to resolve all commented issues in 2-3 days, I am sure you will be able to pull this off.

any updates on the above will be closing this PR, wanted to give chance to others.