Create test framework

[brainelectronics]

Added

• TCP host example script
• JSON file to set registers on TCP/RTU device
• Bash script to wrap manipulation of TCP modbus register data
• Example boot script
• TOC in README
• Use changelog-based-release action to create a draft release with every merge to develop
• Use changelog-based-release action to create a drafted prerelease release with every PR build, see #20
• USAGE and SETUP files with more details

Changed

• Add more info to TCP client example script
• Update modules submodule to 1.3.0
• Line breaks are no longer used in this changelog for enumerations
• Issues are referenced as #123 instead of [#123][ref-issue-123] to avoid explicit references at the bottom or some other location in the file

Fixed

• Typo in RTU client example script

[brainelectronics]

• https://github.com/brainelectronics/micropython-modbus/releases/tag/1.2.0-rc5.dev28
• https://test.pypi.org/project/micropython-modbus/1.2.0rc5.dev28/