docs: fix typo in copyright

Author: josecelano

COPYRIGHT

@@ -1,12 +1,11 @@
-Copyright 2023 in the Torrust-Index-Backend project are retained by their contributors. No
-copyright assignment is required to contribute to the Torrust-Index-Backend project.
+Copyright 2023 in the Torrust-Index-Frontend project are retained by their contributors. No
+copyright assignment is required to contribute to the Torrust-Index-Frontend project.
 
 Some files include explicit copyright notices and/or license notices.
 
-Except as otherwise noted (below and/or in individual files), Torrust-Index-Backend is
-licensed under the GNU Affero General Public License, Version 3.0 <LICENSE-AGPL_3_0>. This license applies to all files in the Torrust-Index-Backend project, except as noted below.
+Except as otherwise noted (below and/or in individual files), Torrust-Index-Frontend is
+licensed under the GNU Affero General Public License, Version 3.0 <LICENSE-AGPL_3_0>. This license applies to all files in the Torrust-Index-Frontend project, except as noted below.
 
-Except as otherwise noted (below and/or in individual files), Torrust-Index-Backend is licensed under the MIT-0 license <LICENSE-MIT_0> for all commits made after 5 years of merging. This license applies to the version of the files merged into the Torrust-Index-Backend project at the time of merging, and does not apply to subsequent updates or revisions to those files.
-
-The contributors to the Torrust-Index-Backend project disclaim all liability for any damages or losses that may arise from the use of the project.
+Except as otherwise noted (below and/or in individual files), Torrust-Index-Frontend is licensed under the MIT-0 license <LICENSE-MIT_0> for all commits made after 5 years of merging. This license applies to the version of the files merged into the Torrust-Index-Frontend project at the time of merging, and does not apply to subsequent updates or revisions to those files.
 
+The contributors to the Torrust-Index-Frontend project disclaim all liability for any damages or losses that may arise from the use of the project.