Update NOTICE to reflect accurate copyright

[sarahcec]

Description of changes

Issue #, if available

Checklist for requesting a review

The change in this PR is (choose one, and delete the other options):

• A breaking change requiring a major version bump to vscode-cedar.
• A backwards-compatible change requiring a minor version bump to vscode-cedar.
• A bug fix or other functionality change requiring a patch to vscode-cedar.
• A change "invisible" to users (e.g., documentation, changes to tests, refactoring, etc.)
• A change (breaking or otherwise) that only impacts unreleased or experimental code.

I confirm that this PR (choose one, and delete the other options):

• Updates the CHANGELOG with a description of my change (required for version bumps).
• Does not update the CHANGELOG because my change does not significantly impact released code.

Disclaimer

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice.