Upgrade mxisd (1.4.1 -> 1.4.2)

Looks like we may not have to do this,
since 1.4.2 fixes edge cases for people who used the broken
1.4.0 release.

We jumped straight to 1.4.1, so maybe we're okay.
Still, upgrading anyway, just in case.

roles/matrix-mxisd/defaults/main.yml

@@ -1,6 +1,6 @@
 matrix_mxisd_enabled: true
 
-matrix_mxisd_docker_image: "kamax/mxisd:1.4.1"
+matrix_mxisd_docker_image: "kamax/mxisd:1.4.2"
 matrix_mxisd_base_path: "{{ matrix_base_data_path }}/mxisd"
 matrix_mxisd_config_path: "{{ matrix_mxisd_base_path }}/config"
 matrix_mxisd_data_path: "{{ matrix_mxisd_base_path }}/data"