Fix --token to --bearer-token in documentation

Author: CPBridge

docs/usage.rst

@@ -626,6 +626,6 @@ Store instances to a Google DICOMweb store:
 .. code-block:: none
 
     dicomweb_client --url https://healthcare.googleapis.com/v1beta1/projects/MYPROJECT/locations/us-central1/datasets/MYDATASET/dicomStores/MYDICOMSTORE/dicomWeb \
-        --token $(gcloud auth print-access-token) \
+        --bearer-token $(gcloud auth print-access-token) \
         store instances \
         dicomfiles/*