feature: add version flag

[EvanCley]

Pull Request Description

add version flag for image-syncer app

Describe what this PR does / why we need it

make sure info of app version/branch/commit/timestamp to

Does this pull request fix one issue?

not yet

Describe how you did it

get version info from git when build binary

Describe how to verify it

image-syncer --version

Special notes for reviews

not yet