Bump to 3.9.0

bootstrap

@@ -31,7 +31,7 @@ main(_) ->
     bootstrap_rebar3(),
 
     %% Build rebar.app from rebar.app.src
-    {ok, App} = rebar_app_info:new(rebar, "3.8.0", filename:absname("_build/default/lib/rebar/")),
+    {ok, App} = rebar_app_info:new(rebar, "3.9.0", filename:absname("_build/default/lib/rebar/")),
     rebar_otp_app:compile(rebar_state:new(), App),
 
     %% Because we are compiling files that are loaded already we want to silence

src/rebar.app.src

@@ -3,7 +3,7 @@
 
 {application, rebar,
  [{description, "Rebar: Erlang Build Tool"},
-  {vsn, "git"},
+  {vsn, "3.9.0"},
   {modules, []},
   {registered, []},
   {applications, [kernel,