Update CHANGELOG.md

[jasonpcarroll]

Update CHANGELOG.md with all PRs merged since v3.3.0 for the v3.3.1 release.

Changes include:

• Add write permissions to doxygen generation workflow on main #184 - Add write permissions to doxygen generation workflow on main
• Update manifest to list unity as a test dependency. #182 - Update manifest to list unity as a test dependency
• Add CMakeLists.txt for coreJSON library #181 - Add CMakeLists.txt for coreJSON library
• Remove version numbers from headers. Add library version define. #180 - Remove version numbers from headers. Add library version define
• Fix JSON validation issues concerning missing commas, escaped control characters, and hex escaped 0 value. #179 - Fix JSON validation issues concerning missing commas, escaped control characters, and hex escaped 0 value
• Remove formatting bot workflow #174 - Remove formatting bot workflow
• Follow Security Guide to update YAML files. #173 - Follow Security Guide to update YAML files
• Update GitHub Actions workflows as per security guidelines #172 - Update GitHub Actions workflows as per security guidelines
• Fix link #171 - Fix link
• Adjust proof tooling to support CBMC v6 #170 - Adjust proof tooling to support CBMC v6
• Treat empty JSON object in key-value pair as valid #169 - Treat empty JSON object in key-value pair as valid
• Correctly detect missing key in a key-value pair #167 - Correctly detect missing key in a key-value pair
• Update LTS 202406 information #166 - Update LTS 202406 information
• Use CBMC version 5.95.1 #164 - Use CBMC version 5.95.1