Prepare release/v4.2 for final release

[mark-mockett]

Since the release/* branches are protected, this PR will compile all required changes to the release/v4.2 branch to complete the version 4.2 release.

Running list of needed changes:

• [x] merge main into this branch to bring up to date with DeviceFeed schema changes and recently added documents
• [x] compile release notes on the main readme and the Releases.md readme
  • Main Readme uses relative links
  • Releases.md uses absolute links to the v4.2 tag
• [x] fix all spelling/grammar mistakes and other clarifications
• [x] update schema URLs to point to main
• [x] add update guide (since no properties were refactored in this version, this will briefly discuss new properties and updated descriptions)
• [x] move WorkZoneType schema change from v4.1 schema to v4.2 schema
• [x] add WorkZoneType to list of enumerated types on spec-content/readme.md
• [x] update Work Zone Feed object diagram