Add regex to license check

LICENSE.HEADER

@@ -1,4 +1,4 @@
-Copyright 2021 Yarmo Mackenbach
+Copyright ##[0-9]{4}## ##[a-zA-Z0-9\s]+##
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.

license-checker-config.json

@@ -7,5 +7,6 @@
         "prepend": "# "
       }
     }
-  }
+  },
+  "regexIdentifier": "##"
 }