fix: add proxy support when fetching patches

[timja]

• Ready for review
• Follows CONTRIBUTING rules
• Reviewed by Snyk internal team

What does this PR do?

Adds proxy support when fetching patches, see #112

Let me know if you think this should be refactored into the lib/request/request file,

Where should the reviewer start?

How should this be manually tested?

Any background context you want to provide?

#112

What are the relevant tickets?

Screenshots

Additional questions

[adrukh]

Thanks @timja-kainos, we'll release this fix later this week!

[adrukh]

Merging to a side branch to go through our internal song-and-dance release process 💃

[adrukh]

This is now pushed at 3e409ca and released with https://github.com/snyk/snyk/releases/tag/v1.66.0

Thanks for the contribution!