Update INSTALL.fr.md

La directive "AllowEncodedSlashes NoDecode" doit être placée dans le répertoire <VirtualHost> d'Apache faute de quoi la redirection provoquée par les nouvelles boites d'authentification (nouveaux thèmes) retourne une erreur 404 
3 jobs for patch-1 in 0 seconds (queued for 109 minutes and 10 seconds)
latest
Status Job ID Name Coverage
  Test
failed #24193
docker
test:php5_latest

failed #24195
docker
test:php74_latest

failed #24194
docker
test:php7_latest

 
Name Stage Failure
failed
test:php5_latest Test There has been a timeout failure or the job got stuck. Check your timeout limits or try again
No job log
failed
test:php7_latest Test There has been a timeout failure or the job got stuck. Check your timeout limits or try again
No job log
failed
test:php74_latest Test There has been a timeout failure or the job got stuck. Check your timeout limits or try again
No job log