mail/libspf2: Use TXT RR type rather than deprecated SPF RR type

- Bump PORTREVISION for package change

PR:		278201
Reported by:	Yasuhito FUTATSUKI <freebsd-bug-report-yf@yf.bsdclub.org>
Obtained from:	https://sources.debian.org/patches/libspf2/1.2.10-8.2/abolish-spf-rrtype.patch/
Reference:	https://github.com/shevek/libspf2/pull/14#issuecomment-1747399288