plug-ins: fix plugin-defs for file-heif.
Commit 01e1587e had directly edited the Makefile.am, which was wrong. This file is generated by plugin-defs.pl. Add the proper dependencies for file-heif and regenerate the Makefile.am.
Commit 01e1587e had directly edited the Makefile.am, which was wrong. This file is generated by plugin-defs.pl. Add the proper dependencies for file-heif and regenerate the Makefile.am.