To-cei

Restores backwards compatibility with code using the `Charter/issuers` parameter.

**Full Changelog**: https://github.com/icaruseu/to-cei/compare/v0.2.0...v0.2.1

Rename `issuer` to `issuers` and enable the addition of multiple issuers if so desired.

**Full Changelog**: https://github.com/icaruseu/to-cei/compare/v0.1.7...v0.2.0

Add parsing for *MOM-style* date range texts like `15679999` or `14530799`

**Full Changelog**: https://github.com/icaruseu/to-cei/compare/v0.1.6...v0.1.7

What's Changed
* 0.1.6 by yngwi in https://github.com/icaruseu/to-cei/pull/1

**Full Changelog**: https://github.com/icaruseu/to-cei/compare/v0.1.5...v0.1.6

**Full Changelog**: https://github.com/icaruseu/to-cei/compare/v0.1.4...v0.1.5

**Full Changelog**: https://github.com/icaruseu/to-cei/compare/v0.1.3...v0.1.4