* update all the changelogs
* update only github URLs in README.md
* sed magic
find . -type f -exec sed -i 's_paritytech/parity-ethereum_OpenEthereum/open-ethereum_g' {} \;
* docs: move 2.2 changelog to docs/
* docs: mark parity 2.1 end of life
* docs: add changelog for 2.1.11
* docs: add changelog for 2.2.6
* docs: add changelog for 2.2.7
* docs: add changelog for 2.3.0
* docs: add release notes for 2.3.0
