Pebble v2.2.2

The previous v2.2.1 release had a small regression with TLS-ALPN-01 challenges and the use of the -dnsserver argument. This bugfix release addresses that regression.

Bug-fixes:

• fix TLS-ALPN-01 with custom -dnsserver (thanks @adferrand)

Misc:

• updated project .gitignore (thanks @eggsampler)