liblouis security and bug fix update

2.6.2-21 - A further Coverity fix 1602585 2.6.2-20 - Fix buffer overruns found by Coverity 1602585 2.6.2-19 - Fix two issues found by Coverity 1602585 2.6.2-18 - Apply patch for CVE-2018-12085 1589942 2.6.2-17 - Fix CVE-2018-11577 1585906 - Fix CVE-2018-11684 1588632 - Fix CVE-2018-11685 1588637 ...