Update CHANGELOG for v3.0.0 release

[AwesomeTornado]

Added details for version 3.0.0 release.

Notes

@elsevers Please look over these edits and let me know if there is anything else I should include from here.

Self-Review

1. Are all images < 40 kB and other files < 300 kB (if not, please carefully assess whether it is worth committing them)? Yes
2. Are all files named according to the appropriate naming convention, i.e., dash-case, camelCase, snake case? Yes
3. Do all Markdown files follow the CONTRIBUTING article template? Yes
4. Do all links work in the material that the PR is adding? Yes
5. Is the PR configured to close the correct issue(s)? Yes
6. Did the PR fully address the Approach section of the issue(s) it is closing? Yes

Reviewer Instructions

Reviewers, please copy and paste a suitable review checklist into your review and answer all questions.

Appendix

This section should be the same for all PRs. Do not edit this section when creating a PR.

Review Checklists

Checklists maintained by the eLev lab for research repositories include:

• Report checklist
• Publication archive checklist (select a checklist from the Approach that corresponds to the step this PR seeks to complete).
• Standard checklist (if none of the above apply).

Standard checklist

1. Are all images < 40 kB and other files < 300 kB (if not, please carefully assess whether it is worth committing them)? **Yes or No**
2. Are all files named according to the appropriate [naming convention](https://github.com/Severson-Group/research-repo-template?tab=readme-ov-file#file-naming), i.e., dash-case, camelCase, snake case? **Yes or No**
3. Do all Markdown files follow the [CONTRIBUTING article template](https://github.com/Severson-Group/.github/blob/main/CONTRIBUTING.md#markdown-documentation-template)? **Yes or No**
4. Do all links work in the material that the PR is adding? **Yes or No**
5. Is the PR configured to close the correct issue(s)? **Yes or No**
6. Did the PR fully address the `Approach` section of the issue(s) it is closing? **Yes or No**

Please work on addressing any **No** items.

[elsevers]

This looks right. Thanks @AwesomeTornado.