Release process for CLI

[a-thaler]

Description
The Kyma CLI needs a technical solution for a repeatable release as well as an integration to the organizational release process of Kyma.

AC:

• For every release of CLI there is a new tag and release page available in the repository
• It is possible to create a patch release not based on latest master but on the latest release
• The binaries for a release are available as Github release attachments and the binaries are not created on a local machine
• A Github release is listing all changelogs and release notes
• A Kyma CLI release uses the version number of the related supported Kyma version
• The release process documentation of kyma is adjusted so that when the process finishes, there is a corresponding Kyma CLI release available

Attachments

• @pkosiec recommended to use https://goreleaser.com/
• https://github.com/kyma-project/test-infra/blob/master/prow/jobs/kyma/kyma-artifacts.yaml
• https://github.com/kyma-project/test-infra/blob/master/prow/jobs/kyma/kyma-github-release.yaml
• https://github.com/kyma-project/test-infra/blob/master/development/github-release.sh
• https://github.com/kyma-project/test-infra/blob/master/prow/scripts/build-kyma-artifacts.sh

[suleymanakbas91]

1.2.0-rc1 pre-release is created by goreleaser following the approach documented here.