Fix typo breaking appservice-discord image pull

Related to 69dce03 (PR #2019).

Fixes https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/2022

roles/matrix-bridge-appservice-discord/defaults/main.yml

@@ -7,7 +7,7 @@ matrix_appservice_discord_container_image_self_build: false
 
 matrix_appservice_discord_version: v3.0.0
 matrix_appservice_discord_docker_image: "{{ matrix_appservice_discord_docker_image_name_prefix }}matrix-org/matrix-appservice-discord:{{ matrix_appservice_discord_version }}"
-matrix_appservice_discord_docker_image_name_prefix: "{{ 'localhost/' if matrix_appservice_discord_container_image_self_build else 'ghcr.io' }}"
+matrix_appservice_discord_docker_image_name_prefix: "{{ 'localhost/' if matrix_appservice_discord_container_image_self_build else 'ghcr.io/' }}"
 matrix_appservice_discord_docker_image_force_pull: "{{ matrix_appservice_discord_docker_image.endswith(':latest') }}"
 
 matrix_appservice_discord_base_path: "{{ matrix_base_data_path }}/appservice-discord"