v4.25.4p2

• Support case insensitive error code at Sisimai::Rhost::FrancePTT, import from sisimai/p5-sisimai#347
• Code improvement at Sisimai::Lhost::EinsUndEins for detecting errors and setting the value of rhost, import from sisimai/p5-sisimai#348
• Import Pull-Request from sisimai/p5-sisimai#349, Add 2 error code values at Sisimai::Rhost::FrancePTT, add 3 sample emails into set-of-emails/ directory: rhost-franceptt-04.eml, 05, and 06.
• Code improvement at Sisimai::Lhost::Postfix for setting HELO into the value of smtpcommand in the parsed results. import sisimai/p5-sisimai#350