Git-machete

- Added: an option to the branch rename dialog allowing to keep or discard the remote tracking branch info.
- Added: extra backup keyboard shortcut (`Ctrl + Option + Shift + M`) for opening Git Machete tab on macOS,
in case `Command + Option + Shift + M` is already taken by Kotlin plugin.
- Added: `Yes + Quit` button in Traverse dialogs.
- Improved: push action is no longer blocked by the other machete actions; it can be run in parallel.

- added: `gitmachete/git-machete` Docker image (contributed by mohitsaxenaknoldus)
- fixed: build process stability

- fixed: support for worktrees (reported by kgadek)

- added: `t` alias for `traverse` command
- fixed: remove underscore from `--start-from` flag for `traverse` subcommand

- Improve stability of traverse and slide-out/slide-in actions.

- added: new way of acquiring the github token (from `~/.github-token`)
- fixed: `--fork-point` and `--down-fork-point` options values have to be ancestor of the current branch
- added: fish shell completions (contributed by kgadek)