docs: use ash docs replacements for hex versions (#67)

documentation/getting_started/getting_started_01_basic_setup.md

@@ -15,13 +15,11 @@ Bring in the `ash_authentication` dependency:
 defp deps()
   [
     # ...
-    {:ash_authentication, "~> x.x"}
+    ____mix_dep_ash_authentication____
   ]
 end
 ```
 
-Use `mix hex.info ash_authentication` to quickly find the latest version.
-
 ## Choosing your extensions, strategies and add-ons
 
 Ash Authentication supports many different features, each provided by different

documentation/getting_started/getting_started_02_phoenix.md

@@ -21,7 +21,7 @@ dependency:
 defp deps()
 [
   # ...
-{:ash_authentication_phoenix, "~> x.x"}
+    ____mix_dep_ash_authentication_phoenix____
 ]
 end
 ```

mix.exs

@@ -156,6 +156,7 @@ defmodule AshAuthentication.MixProject do
         "hex.audit",
         "test"
       ],
+      docs: ["docs", "ash.replace_doc_links"],
       test: ["ecto.create --quiet", "ecto.migrate --quiet", "test"]
     ]
   end