Upgrade DeltaCode to Python 3

[mjherzog]

DeltaCode needs to use the same version of Python as ScanCode Toolkit. This issue is to upgrade to match Toolkit v3.x - from that point on we need to keep DeltaCode in sync with SC Toolkit for Python and for any shared dependencies.

[kjuq]

@arnav-mandal1234 @MaJuRG
Hello. I'm very interested in this issue (along with #101 and #102) as my project of GSoC 2020; Support Python3 in DeltaCode and other improvements.
However, #101 looks like being in progress. Is this issue still one of GSoC project?
Can I submit the proposal of this project idea?

[arnav-mandal1234]

@kvoj Yes, sure. Please join the Gitter channel and submit a draft proposal.

[kjuq]

@arnav-mandal1234 Thank you for your response. Okay, I will finish writing the proposal as soon as possible and submit it via Gitter.

[steven-esser]

#162 merged, closing this.