Move UPGRADE to UPGRADE.md

Descriptive title for this enhancement

To make it easier to read the contrib/docs/UPGRADE should be moved to the root of the source and be converted into markdown UPGRADE.md

Actual behavior

UPGRADE is a file containing all the upgrade step from one version to another, its in a special directory and not directly accessible. Also its in pure text and would benefit from a markdown conversion.

Expected behavior

Have a UPGRADE.md in the root of the sources and make it easy for people to see whats has to be done in each upgrade steps

Benefits

Easier to read doc, more people will be able to see it

created branch 5806-move-upgrade-to-upgrade-md

By bmortier on 2018-03-26T16:08:33 (imported from GitLab)

mentioned in merge request !186

By bmortier on 2018-03-26T16:08:33 (imported from GitLab)

closed via commit bcb0ab76

By bmortier on 2018-03-27T07:09:20 (imported from GitLab)

closed via merge request !186

By bmortier on 2018-03-27T07:09:21 (imported from GitLab)

reopened

By bmortier on 2018-03-27T07:24:39 (imported from GitLab)

created branch 5806-move-upgrade-to-upgrade-md

By bmortier on 2018-03-27T07:24:44 (imported from GitLab)

mentioned in merge request !189

By bmortier on 2018-03-27T07:24:45 (imported from GitLab)

mentioned in commit 64477336

By bmortier on 2018-03-27T07:48:23 (imported from GitLab)

mentioned in merge request !190

By bmortier on 2018-03-27T07:49:24 (imported from GitLab)

removed milestone

By bmortier on 2018-04-05T08:58:28 (imported from GitLab)

closed

By bmortier on 2018-04-24T15:55:41 (imported from GitLab)

changed milestone to %FusionDirectory 1.2.1

By bmortier on 2018-04-24T15:55:53 (imported from GitLab)