Add minchansize to sample config file

sample-lnd.conf

@@ -133,6 +133,10 @@
 ; network.
 ; nobootstrap=1
 
+; The smallest channel size (in satoshis) that we should accept. Incoming
+; channels smaller than this will be rejected, default value 20000.
+; minchansize=
+
 ; The alias your node will use, which can be up to 32 UTF-8 characters in
 ; length.
 ; alias=My Lightning ☇