module github.com/mholt/certmagic has been renamed github.com/caddyserver/certmagic,
so upgrade on this module will fail.
fix: micro/micro#835
caddyserver/certmagic@v0.10.6 is Maximum upgradeable version with go version 1.13
Higher version use *tls.ClientHelloInfo.SupportsCertificate which only supported in go 1.14