Fix custom import section in linter configuration

[muzzammilshahid]

Description, Motivation and Context

Update linter configuration to use a custom section for imports with the prefix 'github.com/gammazero' and make corresponding changes.

What is the current behavior?

(You can also link to an open issue here)

What is the new behavior?

(if this is a feature change)

What kind of change does this PR introduce?

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist:

• My code follows the code style of this project.
• I have added tests to cover my changes.
• Overall test coverage is not decreased.
• All new and existing tests passed.
• My change requires a change to the documentation.
  • I have updated the documentation accordingly.

[om26er]

Looks good. cc @KSDaemon

[KSDaemon]

👍🏻 Cool! Thnx!