Add /_synpase/ path to nginx

[PxBCPG]

Problem

• When I tried to reset my password, I ran into a 404 issue because I tried to access the /_synapse/ path

Solution

• Updating the nginx configuration. This is not the best way to do so (I think ??), but at least it works 😉

PR Status

• [x] Code finished and ready to be reviewed/tested
• [x] The fix/enhancement were manually tested (if applicable)

Automatic tests

Automatic tests can be triggered on https://ci-apps-dev.yunohost.org/ after creating the PR, by commenting "!testme", "!gogogadgetoci" or "By the power of systemd, I invoke The Great App CI to test this Pull Request!". (N.B. : for this to work you need to be a member of the Yunohost-Apps organization)

[PxBCPG]

I manually changed my config directly by changing the nginx configuration. So I kinda tested it but I didn't re-installed it entirely

[Josue-T]

!testme

[yunohost-bot]

Fingers crossed!

[Josue-T]

Let's merge as it's issue with the repos not with the package