The golang version always needs to be in sync between the go.mod, the PR
checklist and the installation instructions.
We also shorten the Pull Request template by removing everything that we
have a CI check for and just refer to those checks instead.
- Update Go version 1.11 to 1.12
- Fix broken link in GitHub PR template
- Fix inconsistent number of spaces after checkbox
- Add proper link to "Ideal Git Commit structure"
