libcap: Update to version 2.67

libcap: Update to version 2.67

- Update from version 2.66 to 2.67
- Update of rootfile
- Changelog
Release notes for 2.67
    Replace use of fgrep with grep -F (POSIX grep flags preferred by GNU grep) - patch
     from David Seifert.
    Added SPDX identifiers to License file(s). Hopefully this will help the various
     robots out there correctly identify the longstanding licenses for libcap and friends.
      (Bug: 216609 reported by Günther Noack)
    Started down the rabbit hole of trying to address (Bug: 216610 reported by Günther
     Noack on behalf of Michael Stapelberg)
        The basic issue is how to link C code with Go psx without using CGo. This is all
         a low level hackery. If you are interested, browse the source.
    Correct for bad whatis entries in man pages (this was throwing a Debian build test,
     detail)
        Also reviewed man pages and addressed cross linkage issues (Bug: 216585)
        Cleaned up some README.md files (made a github mirror now just so I can
         automatically render them).
    Changed meaning of DYNAMIC=no builds.
        This now builds everything with static linking except for libc. The reason for
         this exception is explained in the commit message.
    Inserted demonstration exploit code in capso.so to support article.

Signed-off-by: Adolf Belka <adolf.belka@ipfire.org>