Fix Ansible 2.8 deprecation in Dimension role

roles/matrix-dimension/defaults/main.yml

@@ -15,8 +15,8 @@ matrix_dimension_base_path: "{{ matrix_base_data_path }}/dimension"
 matrix_dimension_docker_image: "turt2live/matrix-dimension:latest"
 
 # The user and group id correspond to the node user in the `turt2live/matrix-dimension` image.
-matrix_dimension_user_uid: 1000
-matrix_dimension_user_gid: 1000
+matrix_dimension_user_uid: '1000'
+matrix_dimension_user_gid: '1000'
 
 # Controls whether the matrix-dimension container exposes its HTTP port (tcp/8184 in the container).
 #