container: lib_taxes: fix arg parsing for 'all' years

Impl was not able to process 'all' years because global_arg_year was set

container/src/finance/lib/internal/lib_taxes.bash

@@ -284,11 +284,12 @@ function lib_taxes::__parse_args()
       lib_utils::die_usage "$_usage"
     fi
     global_arg_year="$_arg_year"
-    declare -gr global_arg_year
+    declare -g global_arg_year
     if [ "$global_arg_year" == "all" ]; then
       # Implementation will treat an empty as all years
       unset global_arg_year
     fi
+    declare -r global_arg_year
   else
     global_arg_year="$(date +%Y)" # Set default
     declare -gr global_arg_year