Change the Keep-Alive idle timeout to 95 seconds (#263)

For consistency with the timeout chosen by other languages since #261 landed:
- heroku/heroku-buildpack-php#823
- heroku/ruby-getting-started#190

GUS-W-18319007.

Signed-off-by: Ed Morley <501702+edmorley@users.noreply.github.com>

Author: edmorley

gunicorn.conf.py

@@ -54,7 +54,7 @@
 # connections is always initiated by the router and not gunicorn, to prevent a race condition
 # if the router sends a request to the app just as gunicorn is closing the connection:
 # https://devcenter.heroku.com/articles/http-routing#keepalives
-keepalive = 100
+keepalive = 95
 
 # Enable logging of incoming requests to stdout.
 accesslog = "-"