Log Message:
Update to 3.015

Upstream changes:
version 3.015: Mon 11 Dec 09:58:17 CET 2023

        Fixes:
        - accept empty fields without complaint. [Andy Beverley]
        - fix counting epilogue trailing blank [Gregor Herrmann] GitHub#18, RT#150141

version 3.014: Wed 18 Oct 12:16:55 CEST 2023

        Changes:
        - handle utf8 in address phrases, according to RFC5335 (since
          2008 experimental)  May show some changes in your regression
          tests.  [Andy Beverley]

        Fixes:
        - epilogue starter test needs ^ anchor
          github issue #16 [Jacob Balazer]
        - existing preamble should keep at least one empty string to
          indicate its existence.
          github issue #18 [Jacob Balazer]
        - clean error when field names are too long w.r.t. the fold
          wrap.  Found by [Raphaël Gertz]