Remove pull_request_template.md
Remove pull_request_template.md

The pull request template is confusing. The only information that seems to matter is to let users know that they need to sign their commits (but we can just enforce this through a setting). This commit removes the template as it's not needed.
mozilla-iam/sso-dashboard,mozilla-iam/sso-dashboard,mozilla-iam/sso-dashboard,mozilla-iam/sso-dashboard