Reflect the correct copyright holders in the license file and package metadata

These are the names of the people who actually produced this work.  Since
under German law copyright is not transferrable (eg, in the US style of "work
for hire"), these are still the copyright holders, though possibly certain
rights have been transferred to another entity/entities.

LICENSE

-PrivateStorage.io Inc. (c) 2020-2022
+Copyright 2020-2023
+Jean-Paul Calderone
+Shae Erisson
+meejah
 
 All rights reserved.
 
@@ -13,7 +16,7 @@ modification, are permitted provided that the following conditions are met:
       disclaimer in the documentation and/or other materials provided
       with the distribution.
 
-    * Neither the name of Author name here nor the names of other
+    * Neither the names of The Authors here nor the names of other
       contributors may be used to endorse or promote products derived
       from this software without specific prior written permission.
 

tahoe-chk.cabal

@@ -13,7 +13,7 @@ bug-reports:
 
 author:             Jean-Paul Calderone
 maintainer:         PrivateStorage.io, Inc.
-copyright:          2020-2022 PrivateStorage.io, Inc.
+copyright:          2020-2023 The Authors
 license:            BSD3
 license-file:       LICENSE
 category:           Cryptography,Library,Parsers,Security