Complete github community standards checklist

[MetricMike]

https://github.com/MetricMike/asdf-awscli/community

• Description
• Code of conduct (consider opening issue on https://github.com/asdf-vm/asdf-plugin-template/issues?q=code+of+conduct ?)
• Security policy (see: default security file  asdf-vm/asdf-plugin-template#3)
• Pull request template (https://github.com/MetricMike/asdf-awscli/blob/main/.github/PULL_REQUEST/pull_request_template.md doesn't count?)