docs/security.txt: Use a SHA-1 hash in the csrf token example
docs/security.txt: Use a SHA-1 hash in the csrf token example

CSRF tokens are now SHA-1 hashes rather than SHA-256 hahses.

Signed-off-by: Andrew Clayton <02e0a999c50b1f88df7a8f5a04e1b76b35ea6a88@digital-domain.net>

ac000/fcgi_app_core,ac000/fcgi_app_core