Log Message:
mail/spamassassin: Update to 3.4.5

This is a micro-update carrying a fix for
  https://cve.mitre.org/cgi-bin/cvename.cgi?name=2020-1946

Upstream changes:

In addition to the CVE which shall be announced separately, this release
includes fixes for the following:

  - Improvements to OLEVBMacro and AskDNS plugins
  - Received and EnvelopeFrom headers matching improvements
  - userpref SQL schema fixes
  - rbl and hashbl evaluation improvements
  - fix for non working TxRep tag names
  - man page fixes