security: Create codeql-analysis.yml

[dustincrogers]

Thanks for contributing the Netlify plugins directory!

Adding codescanning workflow

Are you adding a plugin or updating one?

• Adding a plugin
• Updating a plugin

Have you completed the following?

• Read and followed the plugin author guidelines.
• Included all required fields in your entry.
• Tested the plugin locally and on Netlify, using the plugin version stated in your entry.

Test plan
Please add a link to a successful public deploy log using the stated version of the plugin. Include any other context reviewers might need for testing.

[conventional-commit-lint-gcf]

🤖 I detect that the PR title and the commit message differ and there's only one commit. To use the PR title for the commit history, you can use Github's automerge feature with squashing, or use automerge label. Good luck human!

-- conventional-commit-lint bot
https://conventionalcommits.org/