Use PR erlfmt

Author: maennchen

rebar.config

@@ -13,7 +13,9 @@
     %% https://github.com/markusn/coveralls-erl/pull/36
     {coveralls, ".*",
         {git, "https://github.com/RoadRunnr/coveralls-erl.git", {branch, "feature/git-info"}}},
-    erlfmt,
+    %% Revert back to released version when this PR is merged & released:
+    %% https://github.com/WhatsApp/erlfmt/pull/351
+    {erlfmt, ".*", {git, "https://github.com/maennchen/erlfmt.git", {branch, "support_maybe"}}},
     rebar3_hank,
     rebar3_lint
 ]}.