Release 1.6.12

Notables changes:
 2020-09-16 26bd196 actionless feat(config, urllib, build): add new config options for proxying only aur but not downloadable build sources
 2020-09-03 b50f393 actionless fix(aur: get_repo_url): use aur base url from config
 2020-08-18 d56f705 Felix Glaser fix(locale): update german translations and fix command-shortcuts (#510)
 2020-08-11 c76b5e1 actionless fix(install cli: clone aur repos): don't give up until canceled (fixes #509)