Small inconsistency in license file

[juliangilbey]

A minor matter.

The README.md file says:

*Copyright © 2009–2023 [Spyder Project Contributors](
https://github.com/spyder-ide/spyder/graphs/contributors)*

*Some source files and icons may be under other authorship/licenses; see
[NOTICE.txt](https://github.com/spyder-ide/spyder/blob/master/NOTICE.txt).*

but the LICENSE.md file says:

Copyright (c) 2009- Spyder Project Contributors and others (see AUTHORS.txt); the spyder/images dir and some source files under other terms (see NOTICE.txt)

It would be good if they said exactly the same thing as each other!

Though the AUTHORS.txt file hasn't been updated in about 4 years, it still seems up-to-date. The only information contained in it that does not also appear in LICENSE.md is:

• The original Spyder author (Pierre) and the current maintainer (Carlos)
• The reference to the contributors on GitHub.

[ccordoba12]

Thanks for reporting @juliangilbey. We'll drop the last copyright year in our Readme because it's the simplest thing to do.