Add The WebSocket Protocol

[browser-specs-bot]

Close #1574, adding the suggested spec to the list.

Changes to index.json

This update would trigger the following changes in index.json:

Add spec (1)

```json { "url": "https://www.rfc-editor.org/rfc/rfc6455", "seriesComposition": "full", "shortname": "rfc6455", "series": { "shortname": "rfc6455", "currentSpecification": "rfc6455", "title": "The WebSocket Protocol", "shortTitle": "The WebSocket Protocol", "nightlyUrl": "https://www.rfc-editor.org/rfc/rfc6455" }, "organization": "IETF", "groups": [ { "name": "BiDirectional or Server-Initiated HTTP Working Group", "url": "https://datatracker.ietf.org/wg/hybi/" } ], "nightly": { "url": "https://www.rfc-editor.org/rfc/rfc6455", "status": "Proposed Standard", "alternateUrls": [ "https://datatracker.ietf.org/doc/html/rfc6455", "https://tools.ietf.org/html/rfc6455" ], "filename": "rfc6455.html" }, "title": "The WebSocket Protocol", "source": "ietf", "shortTitle": "The WebSocket Protocol", "categories": [ "browser" ], "standing": "good" } ```

Tests

These changes look good! 😎