Add information on Changelogs.

- Section: [Contributor Friendly Repository](https://harshkapadia2.github.io/git_basics/#_contributor_friendly_repository)
- Learn about Changelogs and add that information **in your own words** in `changelog.adoc` in the https://github.com/HarshKapadia2/git_basics/tree/main/src/content/contributor_friendly_repo directory.
- Make sure to add a reference to the file in the https://github.com/HarshKapadia2/git_basics/blob/main/src/refs/contributor_friendly_repo.adoc file.
- Make sure to read the https://github.com/HarshKapadia2/git_basics/blob/main/CONTRIBUTING.md file fore more instructions.
- Feel free to reference any resources to add information. **It would be better to reference multiple resources.**
- Eg: [Keep a Changelog](https://keepachangelog.com/en/1.1.0)
- Write about a changelog is, the need for a changelog, the format of a changelog, when to update a changelog, etc.