Replace MITRE in project statement "maintainers" section (#266)

* Update project statement in README

Indicate that project is maintained by the HL7 community.

* Update copyright date in README

---------

Co-authored-by: Chris Moesel <cmoesel@users.noreply.github.com>

README.md

@@ -8,7 +8,7 @@ For more information about the evolving FSH syntax see the [FHIR Shorthand Refer
 
 ## FHIR Foundation Project Statement
 
-* Maintainers: This project is maintained by The MITRE Corporation.
+* Maintainers: This project is maintained by the HL7 community.
 * Issues / Discussion: For GoFSH issues, such as bug reports, comments, suggestions, questions, and feature requests, visit [GoFSH Github Issues](https://github.com/FHIR/GoFSH/issues). For discussion of FHIR Shorthand and its associated projects, visit the FHIR Community Chat @ https://chat.fhir.org. The [#shorthand stream](https://chat.fhir.org/#narrow/stream/215610-shorthand) is used for all FHIR Shorthand questions and discussion.
 * License: All contributions to this project will be released under the Apache 2.0 License, and a copy of this license can be found in [LICENSE](LICENSE).
 * Contribution Policy: The GoFSH Contribution Policy can be found in [CONTRIBUTING.md](CONTRIBUTING.md).
@@ -99,7 +99,7 @@ For the best experience, developers should use [Visual Studio Code](https://code
 
 # License
 
-Copyright 2020 Health Level Seven International
+Copyright 2020-2024 Health Level Seven International
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.