Fix git installation bug during synapse-simple-antispam installation

Fixes #424 (Github Issue).

roles/matrix-synapse/tasks/ext/synapse-simple-antispam/setup_install.yml

@@ -16,7 +16,7 @@
 - name: Ensure git installed (Debian)
   apt:
     name:
-      - openssl
+      - git
     state: present
     update_cache: no
   when: "ansible_os_family == 'Debian'"