choosealicense.com and SPDX mismatch for CECILL-2.1

I noticed that CECILL-2.1 appears in French in choosealicense.com, while SPDX uses the English version. This is not on par with some of the requirements in the "Adding a license" documentation [1], such as "the text of the license should match the corresponding text found in spdx/license-list-data".

[1]https://github.com/github/choosealicense.com/blob/gh-pages/CONTRIBUTING.md#adding-a-license