feat: Use Go 1.16.x to avoid darwin arm64 issue

Use Go 1.16.x

Merge pull request mercari#78 from yuya-takeyama/google-cloud-build

Support Google Cloud Build

Merge pull request mercari#74 from mercari/dylan/result-label-set

Merge pull request mercari#72 from mercari/dylan/no-change-label

Merge pull request mercari#67 from fujiwara/github-actions

Add support to GitHub Actions

Merge pull request mercari#68 from mercari/dylan/fix-failed-parse

update fail regex to handle new error text

Merge pull request mercari#46 from shogo82148/fix-fmt-diff-parser

fix that tfnotify fmt reports incorrect result

Merge pull request mercari#60 from timothegenzmer/fix-large-input

scan stdin by byte instead of line

Merge pull request mercari#66 from drlau/dylan/try-parse-merge-pr-number

try parsing pr number to create apply result comment on merged pr