feat(dev): GitHub Codespaces Configuration

[ScottBrenner]

This Pull Request proposes a configuration for GitHub Codespaces, files created by Using a pre-built container configuration, see devcontainer.json reference for specifics.

When Codespaces becomes generally available, you will be billed for storage and compute usage, so I'll probably delete these configurations then .. but for now, this makes it easy to get up and running with developing for this Action - simply open the Codespace, it'll npm install automatically, and you're ready to go!:

node ➜ /workspaces/cfn-lint-action (feature/github-codespaces-config ✗) $ node index.js 
[command]/usr/bin/python3 --version
Python 3.7.3
[command]/usr/bin/python3 -m venv /tmp/setup-cfn-lint-a1hciw/.venv
...
Successfully installed attrs-20.3.0 aws-sam-translator-1.35.0 boto3-1.17.57 botocore-1.20.57 cfn-lint-0.48.3 decorator-4.4.2 importlib-metadata-4.0.1 jmespath-0.10.0 jsonpatch-1.32 jsonpointer-2.1 jsonschema-3.2.0 junit-xml-1.9 networkx-2.5.1 pyrsistent-0.17.3 python-dateutil-2.8.1 pyyaml-5.4.1 s3transfer-0.4.2 six-1.15.0 typing-extensions-3.7.4.3 urllib3-1.26.4 zipp-3.4.1
::add-path::/tmp/setup-cfn-lint-a1hciw/bin
##[add-matcher]/workspaces/.github/cfn-lint.json

[ScottBrenner]

Added some inline notes about the changes. If we think this looks good, I'll add details to https://github.com/ScottBrenner/cfn-lint-action#running-locally about using it! (also https://docs.github.com/en/communities/setting-up-your-project-for-healthy-contributions/setting-guidelines-for-repository-contributors)

[NickLiffen]

@ScottBrenner nice work 💯 This is a good change! I think update the Running Locally section to include this option and we can look at getting this merged 👍

[NickLiffen]

Update Running Locally section 👍

[ScottBrenner]

Sure, how about changing "Running Locally" to "Development"?: 9dea936

addressed