The README after gen-socle does not use the correct path to the output directory

When we generate the configuration files in a custom directory, the README always report the install directory as ./install:

./build -c /srv/mim-libre/prod/laboite/vars.ini -o /srv/mim-libre/prod/laboite/install/ gen-socle
[…]
docs/README

Pour installer la boîte:
cd ./install 
bash deploy
[…]

The templates/docs/README jinja template must use the output directory.