Update matrixdotorg/dendrite-monolith Docker tag to v0.15.1

Author: renovate[bot]

roles/custom/matrix-dendrite/defaults/main.yml

@@ -29,7 +29,7 @@ matrix_dendrite_docker_image_registry_prefix: "{{ 'localhost/' if matrix_dendrit
 matrix_dendrite_docker_image_registry_prefix_upstream: "{{ matrix_dendrite_docker_image_registry_prefix_upstream_default }}"
 matrix_dendrite_docker_image_registry_prefix_upstream_default: docker.io/
 # renovate: datasource=docker depName=matrixdotorg/dendrite-monolith
-matrix_dendrite_docker_image_tag: "v0.15.0"
+matrix_dendrite_docker_image_tag: "v0.15.1"
 matrix_dendrite_docker_image_force_pull: "{{ matrix_dendrite_docker_image.endswith(':latest') }}"
 
 matrix_dendrite_base_path: "{{ matrix_base_data_path }}/dendrite"