Release 2.1.2

[lsigrist]

Pull request to track changes and release related tasks for RocketLogger version 2.1.2.

Release Checklist

• [x] test coverage
  • [x] trigger automated tests
  • [x] execute system tests
• [x] validate effectiveness of bugfixes
  • [x] #105
  • [x] #106
  • [x] #107
• [x] add changelog
  • [x] cross check issues
  • [x] credit for patches
• [ ] review and update documentation
• [x] software update instructions
• [x] verify upgrade path from previous version with data SD card
• [x] perform release
  • [x] merge and tag version on master
  • [x] create github release
  • [x] generate and upload system image and Python packages
  • [ ] verify generated docs