Extend --issue flag to take in args

[sgoudham]

Description

The current --issue flag doesn't take in any arguments to open up a custom issue, we should extend this command to take in an issue number so a custom issue can be opened that's not part of the branch name.

Acceptance Criteria

Given a user that wants to open the issue 42 on the repository sgoudham/git-view
When the user invokes git view --issue 42
Then the following URL should be opened on the browser https://github.com/sgoudham/git-view/issues/42