Is your feature request related to a problem? Please describe.
We're using the changelog feature to output markdown and render it for our clients to see. This works great, however the output is not quite what we're looking for. Right now we're applying a lot of transforms on the output to make it work for us.

Some examples:

• Replacing single quotes with backticks for inline codeblocks
• Replacing h2 headers with h3 to make them smaller

Describe the solution you'd like
We would like to create our own version of the markdown template and be able to pass the custom template file path as a CLI flag to replace the default markdown template.

Describe alternatives you've considered
An alternative is applying transforms on the default output that we're currently doing.

Additional context
N/A