Move to main branch (#2280)

Work CI-CD

- Temporarily disable publishing nuget helpers from main.

Merge pull request #2021 from nanoframework/release-v1.6.6

Release release-v1.7.0

Release release-v1.6.5


***PUBLISH_RELEASE***

Work CI-CD

- Rename master with main.

Work CI-CD

- Set Ruby version to 2.7.

Update Windows.Devices.Spi declaration (#1732)

Merge pull request #1731 from nanoframework/release-v1.5.0

Release release-v1.5.0