LetsEncrypt: Wildcard support

Starting from today, you can issue wildcard certificates using a client that supports ACME v2 (acme.sh for example).

Some useful links:

• The announce
• Technical information about ACMEv2

LetsEncrypt is a non-profit organization, so they need a lot of support from the community. Consider to donate to them or become a sponsor if you're using LE in production.