Log Message:
p5-Plack: update to 1.0045.

1.0045  2017-12-31 12:40:52 PST
    [BUG FIXES]
        - Protect WrapCGI against SIGCHLD handlers #596

    [IMPROVEMENTS]
        - Set Content-Length to 0 in XSendfile middleware #602
        - Document options for XSendfile middleware
        - Remove #foo file for testing that was causing issues on Win32 systems #599
        - Add 103 Early Hints to Plack::Handler::CGI