mobx-state-tree changes

Note from the maintainer: we are releasing a "feature-level" 5.x release due to mst-middlewares and mobx-state-tree versions being synchronized. However, mobx-state-tree does not have any significant changes in this release. We plan to decouple mst-middlewares and mobx-state-tree in the future to avoid this issue. Sorry about any issues this causes!

• Docs: Include Instance import in docs (#1834 by @hgulersen and @elektronik2k5)
• CI: Return coverage report (#1819 by @pustovalov)
• Minor refactors (#1800, #1801, #1802 by @rluvaton)

mst-middlewares changes

• Add includeHooks flag to UndoManager (#1796 by @andrezzoid)
• Update mobx-state-tree peerDependency in mst-middlewares (#1824 by @Tucker-Eric, @FreeFrags, and @ruudandriessen)