Restore authentication-type attribute (#22)

Restore the authentication-type attribute as discussed in tableau/connector-plugin-sdk#646

Author: CJStuart

tableau-databricks/connection-resolver.tdr

@@ -32,6 +32,7 @@ limitations under the License.
                     <attr>authentication</attr>
                     <attr>username</attr>
                     <attr>password</attr>
+                    <attr>authentication-type</attr>
                     <attr>instanceurl</attr>
                     <attr>odbc-connect-string-extras</attr>
                     <attr>ACCESSTOKEN</attr>