switch to soranoba's mustache repo

rebar.config

@@ -11,9 +11,9 @@
        {relx, "",
         {git, "https://github.com/tsloughter/relx.git",
          {branch, "mustache"}}},
-       {mustache, "",
-        {git, "https://github.com/tsloughter/mustache.git",
-         {branch, "master"}}},
+       {mustache, ".*",
+         {git, "https://github.com/soranoba/mustache.git",
+          {branch, "master"}}},
        {getopt, "",
         {git, "https://github.com/jcomellas/getopt.git",
          {branch, "master"}}}]}.