update scalastyle; add scapegoat and scalafmt

[philvarner]

Signed-off-by: philvarner philvarner@gmail.com

Overview

0. refactor scala versions out into variables
1. updates scalastyle dependency to the maintained 'beautiful-scala' package instead of the abandoned one
2. adds scapegoat configuration for static analysis (similar to config in stac4s)
3. add scalafmt (off by default-- maybe at some point all the code should be reformatted in one PR). The .scalafmt.conf was copied from stac4s

Checklist

• n/a ./CHANGELOG.md updated, if necessary. Link to the issue if closed, otherwise the PR.
• n/a Module Hierarchy updated, if necessary
• n/a docs guides update, if necessary
• n/a New user API has useful Scaladoc strings
• n/a Unit tests added for bug-fix or new feature

Demo

none

Notes

none

[pomadchin]

I'd like to see Version.scala212 as the default here. :D
2.11 is not a priority atm, more like a legacy crossompilation that I'd really like to drop.
We use GT mostly with 2.12.

[philvarner]

sorry, that must have been a typo when I originally made this change -- I've been cross-compiling most of the time and didn't notice.

[pomadchin]

Does scalafmtAll breaks everything? :/ I'd expect it to reformat 90% of our files.

[philvarner]

It does -- I mostly just wanted to get it in here, but have it be unused. But, I think it would be better to spend a bit of time aligning the rules with the existing code before merging. Putting PR in draft.

[pomadchin]

There is this tool that hopefully can generate the scalafmt file that would fit our needs: https://github.com/tanishiking/scalaunfmt

(I haven't tried it and I would not be that positive about it), scalafmt is definitely going to break our type params with lots of imports formatting ):

[philvarner]

Great, I'll take a look at that tool. I think it's more important to be consistent within the codebase than adhere to some arbitrary external standard, so I'll try to write the rules that way.