👷 Feat: Replace Travis w/ GitHub Actions CI (#912)

* Feat: add GH Actions

* forgot a sudo lol

* don't need to update

* upload dist once done

* rename to linux.yml

* rename name too

* add other platforms

* rename platforms

* fix windows maybe?

* spelled install wrong lol

* add code cov

* add snyk env

* fix env

* install npm

* delete snyk workflow

* don't install runtime dependencies before build script on win32

* win32 build script: respect README instructions

* Fix: fix travis cli for manos & linux (#911)

* fix: cache npm

* better artifact naming attempt

* cache electron binaries used by electron-builder

* better AppImage artifact naming

* banish travis

* test which platforms need python

* add publishing code

* move it to the right place

* always publish new draft

* load token

* let electron-builder figure out whether to publish artifacts or not

* cleanup some Snyk stuff

* remove .snyk

* Make a unified Workflow with multiple platforms as Jobs

* remove individual os-specific workflows, use unified workflow instead

Co-authored-by: Gabriel Saillard <gabriel@saillard.dev>