SpringBoot Update and rename LICENSE.txt to LICENSE

Remove boilerplate from license.
Rename to LICENSE, which is the current default name for a LICENSE in a GitHub repository.

Comment From: philwebb

Thanks for the PR but most Spring projects use LICENSE.txt which is still recognized by GitHub. I think we should also leave the appendix section.

Comment From: thomasturrell

@philwebb thank you for taking the time to review my pull request.

An additional issue that I resolved in this pull request replacing the template:

Copyright {yyyy} {name of copyright owner}

with:

Do you think it is worth me opening another pull request with just this (minor) change?

Comment From: thomasturrell

Copyright 2002-2022 Pivotal, Inc.

Although I believe that this should now be

Comment From: philwebb

@thomasturrell I think we usually leave that template information as it is in the LICENCE.txt file. For example, here is the one from Spring Framework.

We do update the copyright in source files that we change. For example, here's a recent commit where I updated the date. We use "the original author or authors" rather than "Pivotal" or any specific company.