v1.6.1

Changelog

87f86f1 Add loglevel flag for multiroot-ca
29ae05f Merge pull request #1189 from cloudflare/nicky/fix-coreos-mod-rename
1f29b04 Merge pull request #1191 from Rutori/loglevel-multiroot-ca
f4208c6 Merge pull request #1195 from BowonY/bowon/avoid-select-all
b2552ca fix upgrading transitive coreos dependency breakage
19c09ff pick columns to get revoked/unexpired certs
e582ed4 remove -u flag from readme, link to releases
bea2d3d remove old go versions from travis