fixup! update hookshot private key installation method

roles/matrix-bridge-hookshot/templates/config.yml.j2

@@ -15,7 +15,7 @@ github:
     # Authentication for the GitHub App.
     #
     id: {{ matrix_hookshot_github_appid }}
-    privateKeyFile: /data/{{ matrix_hookshot_github_private_key }}
+    privateKeyFile: /data/{{ matrix_hookshot_github_private_key_file }}
   webhook:
     # Webhook settings for the GitHub app.
     #