Update go installation docs to version 1.6.2
Update go installation docs to version 1.6.2

hu19891110/gitlab-ci-multi-runner,ayufan/gitlab-ci-multi-runner,ayufan/gitlab-ci-multi-runner,hu19891110/gitlab-ci-multi-runner,soiff/gitlab-ci-multi-runner,hu19891110/gitlab-ci-multi-runner,soiff/gitlab-ci-multi-runner,soiff/gitlab-ci-multi-runner,ayufan/gitlab-ci-multi-runner