Update branch patterns

[dron22]

This PR updates branch patterns:

• Add doc/... branch pattern for documentation related changes. (will not bump versions, but do a prerelease increment)
• Add misc/... branch pattern for other non-source-code related changes. (will not bump versions, but do a prerelease increment)
• Remove plural branch patterns, as our contributing guidelines explicitly states, that "Each pull request should address a single bug fix or feature." (https://github.com/wakatime/wakatime-cli/blame/develop/CONTRIBUTING.md#L40)

The adjustment is done in semver repo, as our contributing guidelines refer to semver documentation regarding branch naming (https://github.com/wakatime/wakatime-cli/blame/develop/CONTRIBUTING.md#L31)

Addresses https://github.com/wakatime/wakatime-cli/issues/349