Bump dependencies flagged by dependabot

[Shinomix]

What this PR does

In this PR we bump all the dependencies flagged by dependabot as having alerts:

• terser-webpack-plugin~5.3.11, sub-dependency of webpack to patch serialize-javascript
• karma~6.4.4, to include socket.io^4.7.2
• socket.io-adapter, sub-dependency of karma to include ws~8.17.1
• rack~2.2.13 to include CVE patches

With all these bumps, we should be able to pass the dependabot step again and rollout the gem to Rubygems.

Reviewer's guide to testing

These are development dependencies, if CI is green this shouldn't cause any problem nor require further testing.

Checklist

Before submitting the PR, please consider if any of the following are needed:

• Update CHANGELOG.md if the changes would impact users
• Update README.md, if appropriate.
• Update any relevant pages in /docs, if necessary
• For security fixes, the Disclosure Policy must be followed.