Mailman 2.1.35 security release

Related Vulnerabilities: CVE-2021-42096   CVE-2021-42097  
                Quoting from Mark Sapiro's emails at:
https://mail.python.org/archives/list/mailman-announce () python org/thread/IKCO6JU755AP5G5TKMBJL6IEZQTTNPDQ/

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        -Alan Coopersmith-               alan.coopersmith () oracle com
         Oracle Solaris Engineering - https://blogs.oracle.com/alanc