version number and readme update on release

When a release is made, I have a need to
- Generate a file with the version number of the tag being generated. (this allows to ensure that my deno script always report the correct version number)
- Update the readme links to display current version.

I have created a fork with a raw prototype to suit my need (see https://github.com/sylc/release/pull/1). i.e I created 2 new plugins. one for adding the file with the version number and one for updating the readme.

Would you be interested in getting this supported in the `release` repo by either:
- adding these plugins to the repo with probably a config file so the user can enable/disable/tweak the behaviour of these plugins
- Or supporting calling external plugins.

I'm happy to help implemented the feature. cheers