Add fractional part of seconds to datetime parser

Some recent Qt version must have changed the output of QDateTime
represented as a string to include that.

templates/defaultfilters/datetime.cpp

@@ -89,7 +89,7 @@ QVariant DateFilter::doFilter(const QVariant &input, const QVariant &argument,
{
  Q_UNUSED(autoescape)
  auto d = QDateTime::fromString(getSafeString(input),
                                 QStringLiteral("yyyy-MM-ddThh:mm:ss"));
                                 QStringLiteral("yyyy-MM-ddThh:mm:ss.zzz"));

  auto argString = getSafeString(argument);