Readme build instructions tweaks

[CodingKoopa]

I'm trying to use the helper program to use pass with Docker. I'm using the armhf architecture on Ubuntu 16.04. Only amd64 releases are provided here, and the Ubuntu backports for these programs don't go far enough to Trusty, so I have to build docker-credential-pass myself. I'm using these commands:

• sudo apt-get install golang-go to install Go.
• cd ~/Documents/ && mkdir Go to make a working directory for Go.
• export GOPATH=$HOME/Documents/Go to set the working directory for Go.
• go get github.com/docker/docker-credential-helpers as instructed by the readme. This outputted this line on Go 1.6.2:

package github.com/docker/docker-credential-helpers: no buildable Go source files in /home/koopa/Documents/Go/src/github.com/docker/docker-credential-helpers

And on Go 1.10.3:

package github.com/docker/docker-credential-helpers: no Go files in /home/koopa/Documents/Go/src/github.com/docker/docker-credential-helpers

• cd $GOPATH/src/github.com/docker/docker-credential-helpers to enter the readme directory. The readme says to use cd $GOPATH/docker/docker-credentials-helpers, which seems to be the wrong path here.
• make pass to compile docker-credential-pass.
• mkdir $GOPATH/bin, ln -s "$GOPATH/src/github.com/docker/docker-credential-helpers/bin/docker-credential-pass" $GOPATH/bin/, and echo "PATH=$PATH:$GOPATH/bin" >> ~/.bashrc to add the binary to my path.

tl;dr: The command in step 1 outputted an error for me, and a command in step 2 has a different path than what I got.

[rouaks]

Same issue

[thaJeztah]

#168 switched this project to use go modules, which should probably help with this issue.

Closing this ticket for now, but feel free to comment if there's things left to address