getTemplateVars does not exist before CiviCRM 5.69

Hi, this one had me stumped for a while - I was getting an undefind error for getTemplateVars().

I eventually worked out that this was for the very good reason that we're still using CiviCRM 5.68, and it was called get_template_vars() before version 5.69. I've patched our copy locally, but this does break your minimum requirements declaration. In 5.69 the deprecated get_template_vars() delegates to getTemplateVars().