Release v0.8.1

Changelog

dccbb7c merge from upstream
b79c0a5 allow pull anonymously
e3ae74a read auth info from repo file, add debug
c95fe93 auth method change to get
1167f06 fix protocal name
b081da8 fix install-plugin script
6f4aded setup go releaser
e865348 fix circleci config
936d94b add go report card, fix gofmt issues, add circleci
e46d1c2 add readme, support auth-token
971384c prep for 0.8.1 release
17794c3 Fix for missing files in Helm 2 charts (#53)
2cbc00f maint: use chartmuseum 0.11.0 for tests