mail/exim: update to 4.95 release (+)

Finally, Exim will be pushed to 4.95 release.
Long wait was caused by some criticals errors in vanilla release,
upstream fixes got a some time to come.

• Apply sendfile patch, fixes SIGSEGV using clamd via TCP [1]
• Convert select() to poll(), fixes crashes (SIGSEV) on FreeBSD 12.2 [2]

PR: 258848 [1], 259822 [2]
Sponsored by: Netzkommune GmbH