Update dehydrated #50

0.4.0 in https://github.com/lukas2511/dehydrated/releases shows the following changes over 0.3.1 (currently in this image):

• dehydrated now asks you to read and accept the CAs terms of service before creating an account
• Skip challenges for already validated domains
• Removed need for some special commands (BusyBox compatibility)
• Exported a few more variables for use in hook-scripts
• fullchain.pem now actually contains the full chain instead of just the certificate with an intermediate cert