prepend history

[juliettelavoie]

Pull Request Checklist:

• This PR addresses an already opened issue (for bug fixes / features)
  • This PR fixes #xyz
• (If applicable) Documentation has been added / updated (for bug fixes / features).
• (If applicable) Tests have been added.
• CHANGELOG.rst has been updated (with summary of main changes).
  • Link to issue (:issue:number) and pull request (:pull:number) has been added.

What kind of change does this PR introduce?

• prepend history instead of appending it. This is what is done is most other software.

Does this PR introduce a breaking change?

well the history won't be in the same order

Other information:

this was changed in xclim recently also

[coveralls]

coverage: 78.443% (-0.2%) from 78.623%
when pulling dccc98e on fix-history
into df579f7 on main.