fix missing vars error

defaults/main.yml

@@ -15,4 +15,5 @@ renovatebot_autodiscover: False
 renovatebot_endpoint: "https://github.company.com/api/v3"
 renovatebot_git_author: "Renovate Bot <bot@renovateapp.com>"
 renovatebot_platform: github
-renovatebot_token:
+# @var renovatebot_token:description: Personal access token for your bot account.
+# renovatebot_token: $ "_unset_"

templates/etc/sysconfig/renovate.j2

@@ -1,7 +1,9 @@
 #jinja2:lstrip_blocks: True
 {{ ansible_managed | comment }}
 
+{% if renovatebot_github_token is defined %}
 GITHUB_COM_TOKEN="{{ renovatebot_github_token }}"
+{% endif %}
 RENOVATE_AUTODISCOVER="{{ renovatebot_autodiscover | bool | lower }}"
 RENOVATE_ENDPOINT="{{ renovatebot_endpoint }}"
 RENOVATE_GIT_AUTHOR="{{ renovatebot_git_author }}"