docs: update release notes

Signed-off-by: Erik Michelson <github@erik.michelson.eu>

chore: bump version to 1.10.2

Signed-off-by: Philip Molares <philip.molares@udo.edu>

chore: update AUTHORS file

Signed-off-by: Philip Molares <philip.molares@udo.edu>

chore: increase version of all relevant files

We release Alpha v3 of HedgeDoc 2.0 and need to make sure that all
version are changed accordingly.

Signed-off-by: Philip Molares <philip.molares@udo.edu>

Bump version to 1.10.0

Signed-off-by: David Mehren <git@herrmehren.de>

chore: release alpha 2

Signed-off-by: Philip Molares <philip.molares@udo.edu>

chore: set version in all packae.jsons

Signed-off-by: David Mehren <git@herrmehren.de>

Bump version to 1.9.9

Signed-off-by: David Mehren <git@herrmehren.de>

Update AUTHORS file

Signed-off-by: David Mehren <git@herrmehren.de>

Merge pull request #3375 from hedgedoc/release/1.9.7