[feature] User agent swap

[elogada]

Hey @droope

Either there's no way to change my User-agent header, or I can't find it in the help docs. Any way you can add a functionality that allows me to change the User-agent of a scan?

Thanks!

[SamJoan]

Hi there,

I'd be willing to accept a PR for this change provided it comes with a unit test. The change would have to occur on this line.

Alternatively you can clone the repository and manually modify the DEFAULT_UA variable for your purposes.

Thanks!
Pedro

[SamJoan]

Just so anybody who needs this knows, @kieran-github has implemented this feature into the development branch.

I will give it a test when I can and merge it into master, as well as release it into PyPi.