Full Changelog

• b9c7c5c Release v1.6.0.pre1
• a107e87 Update version for pre-release (#435)
• d916b45 Fix Stalebot settings to not auto-close old issues/PRs (#433)
• f5cd6a6 Implementation and tests required to ensure that command output encoding does not raise an exception (#405)
• 2402674 Allow consumers to point git binary via env var (#416)
• 9bd4407 Do not allow changes to ENV to leak from test to test (#403)
• a4fbb6b Support merge-base (#370)
• b7a1a67 Add support for unshallow (#377)
• 7d43d23 Adding ruby-head and ruby 2.6 to Travis, removing C ext from repo (#382)