[DOC] give a warning for CSP headers when using subdomain

[divinerites]

Prerequisites

• I have searched open and closed issues to make sure that the feature has not yet been requested.

Feature request

When your site is using some Content Security Policy, you have to add plausible.io in order the .js to load and to work. I guess this is known if you manage your website's header with CSP.

But when you add statsforplausible.mydomain.com in order to go thru Adblock problems, do not forget to add this subdomain specifically to your CSP too.

May be you can add a small warning in the setup documentation page ? I didn't made a doc PR because i do not know your policy for that :-)
HTH.

[divinerites]

Closed. See plausible/docs#4