0.10.6

Backporting fixes:

• Improve len() for ParquetFile. (#2261 by @jaheba)
• Max idle transform fix (#2262 by @jaheba)
• Fix ignore hidden files when generating datasets (#2263 by @kashif)
• Fix: set max idle transforms in PyTorch estimators (#2266 by @lostella)
• Fix QuantileForecast.plot() to use DateTimeIndex (#2269 by @abdulfatir)