Go软件包安装因未知证书颁发机构而失败

I'm attempting to install a Go module from bitbucket as follows:

go get bitbucket.org/kardianos/osext

But I receive the following error:

package bitbucket.org/kardianos/osext: Get https://api.bitbucket.org/1.0/repositories/kardianos/osext: x509: certificate signed by unknown authority

Google lead me to the instructions at this post, which I have followed by editing /etc/mercurial/hgrc to contain:

[web]
cacerts = /etc/ssl/certs/ca-certificates.crt

as instructed for my OS (Debian), however I still receive the same error.

what else can I do?

it looks like I'm still using 1.0.2 (the version provided with Debian wheezy)

Considering that this looks like a Go 1.0 bug, the first thing to check is to upgrade Go to 1.3+.

net/http: use tls host instead of proxy, when checking against a certificate

That could solve the certificate issue.
Golang Debian packages mentions 1.3.2 (but for Debian Jessie, not wheezy)

You can follow "How to install Golang 1.1(+) in Debian from repository " for more.
(Done after "How can I run Debian stable but install some packages from testing?")