Update to 1.60
    
    - New upstream release 1.60
      - Don't make blocking readline if socket was set nonblocking, but return as
        soon no more data are available (CPAN RT#75910)
      - Fix BUG section about threading so that it shows package as thread safe
        as long as Net::SSLeay ≥ 1.43 is used (CPAN RT#75749)
    - BR: perl(constant), perl(Exporter) and perl(IO::Socket)