Security update for python-waitress

Open Source Vulnerabilities openSUSE-SU-2020:1911-1

This update for python-waitress to 1.4.3 fixes the following security issues: - CVE-2019-16785: HTTP request smuggling through LF vs CRLF handling (bsc#1161088). - CVE-2019-16786: HTTP request smuggling through invalid Transfer-Encoding (bsc#1161089). - CVE-2019-16789: HTTP request smuggling through invalid whitespace characters (bsc#1160790). - CVE-2019-16792: HTTP request smuggling by sending the Content-Length header twice (bsc#1161670). This update was imported from the SUSE:SLE-15:Update update project.