Typo in the 'add-apt-repo' command

[wilkmar]

On the 'Set up your development environment' page [1], in the 'Install the Dqlite tooling' section, the following command is incorrect for Ubuntu:
sudo add-apt-repo ppa:dqlite/dev
Instead, it should read as the following:
sudo add-apt-repository ppa:dqlite/dev

[1] https://dqlite.io/docs/tutorials/setup-your-development-environment