pmb.config: add sudo to list of required programs

sudo is installed by default on nearly all distros so it's not
neccessary to mention in the readme but put it in this list to avoid
nasty surprises.

pmb/config/__init__.py

@@ -37,7 +37,7 @@ ondev_min_version = "0.2.0"
 # Programs that pmbootstrap expects to be available from the host system. Keep
 # in sync with README.md, and try to keep the list as small as possible. The
 # idea is to run almost everything in Alpine chroots.
-required_programs = ["git", "openssl", "ps"]
+required_programs = ["git", "openssl", "ps", "sudo"]
 
 # Keys saved in the config file (mostly what we ask in 'pmbootstrap init')
 config_keys = ["aports",