Mantisbt version requirements

This release is intended for installation or upgrading in mantisbt >= 2.26.0 version.
For mantisbt version < 2.26.0 use https://github.com/mantisbt-plugins/Calendar/releases/tag/release-2.6.3

What's Changed

• Fixing a problem with alternative placement of the plugins folder by @brlumen in #67
• Fixed a problem with returning to viewing an event from the editing mode of this event by @brlumen in #68
• Fixes a bug when editing repeating events by @brlumen in #72
• Fixes an error in substituting the current end date of an event repetition into the mini-calendar when editing an event by @brlumen in #73
• Added support for all databases supported by mantisbt by @brlumen in #75

Full Changelog: release-2.7.0...release-2.7.1