Update README, GH actions, etc

[jclusso]

After the repo transfer some links and things were broken or no longer being used. They've been removed now.

Also, I removed the CHANGELOG and created releases for all the old versions with the changes. As we know, it's always confusing when a gem has a CHANGELOG and Releases and you never know which to look at.

[Copilot]

Pull Request Overview

This PR updates repository references and CI configuration following a repository transfer from ElMassimo to cacheventures organization. The changes remove outdated CI configurations and update links to reflect the new repository location.

• Updated repository URLs from ElMassimo to cacheventures organization
• Replaced Travis CI with GitHub Actions workflow
• Simplified README badges and license section

Reviewed Changes

Copilot reviewed 6 out of 7 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
mongoid_includes.gemspec	Updated homepage URL to new repository location
README.md	Updated badges to point to new repository and simplified license section
LICENSE.txt	Added Cache Ventures copyright for 2025
.travis.yml	Removed Travis CI configuration file
.github/workflows/ci.yml	Added new GitHub Actions CI workflow
.github/workflows/build.yml	Removed old GitHub Actions build workflow

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