Identify obsolete snapshots

What's Changed

• feat: identify obsolete snapshots by @gkampitakis in #10

Full Changelog: v0.1.2...v0.1.3

v0.1.2

0.1.2 (2021-12-09)

Bug Fixes

• add unit tests (c21293f)
• colorize spaces and tabs on diff (ef8ccb1)
• use concurrency safe sync.Map (a18d31a)