fix: relax mime and poison gax dependencies

This allows `google_gax` to coexist with projects that depend on newer versions
of these libraries.

Author: tomtaylor

clients/gax/mix.exs

@@ -27,8 +27,8 @@ defmodule GoogleApi.Gax.MixProject do
   defp deps() do
     [
       {:tesla, "~> 1.2"},
-      {:mime, "~> 1.0"},
-      {:poison, ">= 3.0.0 and < 5.0.0"},
+      {:mime, "~> 1.0 or ~> 2.0"},
+      {:poison, ">= 3.0.0 and < 7.0.0"},
       {:ex_doc, "~> 0.16", only: :dev},
       {:dialyxir, "~> 0.5", only: [:dev], runtime: false}
     ]