[5.3] Cleanup repo meta files (#15470)

* Cleanup meta files

* Added `.github export-ignore` to `.gitattributes`

* Don’t move `CONTRIBUTING.md`

.gitattributes

@@ -1,5 +1,6 @@
 * text=auto
 
+/.github export-ignore
 /build export-ignore
 /tests export-ignore
 .editorconfig export-ignore

CONTRIBUTING.md

@@ -1,3 +1,3 @@
 # Laravel Contribution Guide
 
-Thank you for considering contributing to the Laravel framework! The contribution guide can be found in the [Laravel documentation](https://laravel.com/docs/contributions). Please review the entire guide before sending a pull request.
+Thank you for considering contributing to the Laravel framework! The contribution guide can be found in the [Laravel documentation](https://laravel.com/docs/contributions).

LICENSE.md

@@ -1,6 +1,6 @@
 The MIT License (MIT)
 
-Copyright (c) <Taylor Otwell>
+Copyright (c) Taylor Otwell
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal