Pin rebar3_format to its latest version (#9)

Author: Brujo Benavides

rebar.config

@@ -41,6 +41,6 @@
 
 {alias, [{test, [format, lint, xref, dialyzer, eunit, cover]}]}.
 
-{plugins, [rebar3_lint, {rebar3_format, "~> 0.5.0"}]}.
+{plugins, [rebar3_lint, {rebar3_format, "~> 0.6.0"}]}.
 
 {format, [{files, ["src/*.erl", "include/*.hrl"]}]}.