Log Message:
textproc/ruby-kramdown-rfc2629: update to 1.5.6

1.4.17 (2021-06-18)

* Add gymnastics to coding: us-ascii doesn't break with beyond-ASCII bibxml

1.4.18 (2021-06-28)

* Fix various regressions in referencing and other syntax

1.4.19 (2021-07-03)

* kdrfc improvements
* fix remote
* more namechar in section ref

1.5.1 (2021-07-18)

* Separate out kdrfc-processor into a library

1.5.2 (2021-07-18)

* Handle postalLine, anticipate country changes

1.5.3 (2021-07-23)

* Clean up indented quotes, asides, and blockquotes

1.5.4 (2021-07-25)

* kgt fix; text for bare section references

1.5.5 (2021-07-25)

* Add all/last and quote/dedent to {::include}

1.5.6 (2021-07-29)

* New command: de-gfm