def sha_in_release_branch(sha)
      branch = @options[:release_branch] || @fetcher.default_branch
      commits_in_branch = @fetcher.fetch_compare(@fetcher.oldest_commit["sha"], branch)
      shas_in_branch = commits_in_branch["commits"].collect { |commit| commit["sha"] }
      shas_in_branch.include?(sha)
    end
def sha_in_release_branch(sha)
      branch = @options[:release_branch] || @fetcher.default_branch
      commits_in_branch = @fetcher.fetch_compare(@fetcher.oldest_commit["sha"], branch)
      shas_in_branch = commits_in_branch["commits"].collect { |commit| commit["sha"] }
      shas_in_branch.include?(sha)
    end
Detect if a sha occurs in the --release-branch. Uses the github repo
 default branch if not specified.

 @param [String] sha SHA to check.
 @return [Boolean] True if SHA is in the branch git history.