feat(version): introduce version check subcommand

The version subcommand handles pkgver related commands, the first
subcommand being `check`. Check runs nvchecker if a `.nvchecker.toml`
file exists and compares the current pkgver with the latest release.

Introduces nvchecker as optional dependency which has to be installed in
order to use this particular subcommand.

BREAKING CHANGE: formerly pkgctl version would output the version of the
pkgctl tool, now it is used as a version related subcommand.

Fixes #140

Component: pkgctl version
Component: pkgctl version check
Co-authored-by: Christian Heusel <christian@heusel.eu>

0 files changed, 0 insertions, 0 deletions