Sync upgrade notes & changelog
- docs/simplesamlphp-changelog.md 52 additions, 0 deletionsdocs/simplesamlphp-changelog.md
- docs/simplesamlphp-upgrade-notes-2.1.md 7 additions, 0 deletionsdocs/simplesamlphp-upgrade-notes-2.1.md
- docs/simplesamlphp-upgrade-notes-2.2.md 19 additions, 0 deletionsdocs/simplesamlphp-upgrade-notes-2.2.md