"'3' if ansible_python.version.major == 3" fatally exits on systems with Python versions less than 3.  Adding the "else" statement corrects the fatal error.

Install python3-docker if ansible is running python 3

Fix invalid password salts for slack webhooks

Related to #355.

Upgrade Synapse to 1.9.0

Matrix change user admin status

uri.follow_redirects is now a string field

Use Postgres 12.1 when creating a backup

Reword updating-users-passwords.md option 3

Fix regex in matrix_appservice_webhooks_registration_yaml

Related to #339 (Github Pull Request).

Add matrix-appservice-webhooks role.

Upgrade riot-web (1.5.6 -> 1.5.7)

Regression introduced in 53186ffa1c

NeDB is deprecated, so we should transition away from it in the future.
Still, most of the functionality should work on this new version.