Convert markdown to the markup format used in jira

The markup language used in jira is not very common. In contrast, Markdown is widely used and editing it is supported by a lot of editors. I like to keep my documentation in markdown, but when I need to paste them into jira forms, this doesn't work very well. This is where this small command-line tool helps. It uses the great pulldown-cmark library for reading the CommonMark flaver of Markdown either from stdin or from a file, and converts it to the format used in jira, either to stdout or to a file.