Add JWT secret for gitea

This appeared in my config - it's probably important

ansible/roles/gitea/vars/main.yml

@@ -1,6 +1,7 @@
 lfs_jwt_secret: "{{ vault_lfs_jwt_secret }}"
 secret_key: "{{ vault_secret_key }}"
 internal_token: "{{ vault_internal_token }}"
+oauth2_jwt_secret: "{{ vault_oauth2_jwt_secret }}"
 mailer_from_address: "{{ vault_mailer_from_address }}"
 mailer_user: "{{ vault_mailer_user }}"
 mailer_password: "{{ vault_mailer_password }}"