chore(portal): use appropriate sha in dev (#7782)

Not a huge deal, but this doesn't actually need to be a valid SHA and
this is more clear / has no risk of collision with an actual git sha.

elixir/apps/api/mix.exs

@@ -79,7 +79,7 @@ defmodule API.MixProject do
   end
 
   defp version do
-    sha = System.get_env("GIT_SHA", "deadbeef") |> String.trim()
+    sha = System.get_env("GIT_SHA", "dev") |> String.trim()
     "0.1.0+#{sha}"
   end
 end

elixir/apps/domain/mix.exs

@@ -112,7 +112,7 @@ defmodule Domain.MixProject do
   end
 
   defp version do
-    sha = System.get_env("GIT_SHA", "deadbeef") |> String.trim()
+    sha = System.get_env("GIT_SHA", "dev") |> String.trim()
     "0.1.0+#{sha}"
   end
 end

elixir/apps/web/mix.exs

@@ -104,7 +104,7 @@ defmodule Web.MixProject do
   end
 
   defp version do
-    sha = System.get_env("GIT_SHA", "deadbeef") |> String.trim()
+    sha = System.get_env("GIT_SHA", "dev") |> String.trim()
     "0.1.0+#{sha}"
   end
 end

elixir/mix.exs

@@ -95,7 +95,7 @@ defmodule Firezone.MixProject do
   end
 
   defp version do
-    sha = System.get_env("GIT_SHA", "deadbeef") |> String.trim()
+    sha = System.get_env("GIT_SHA", "dev") |> String.trim()
     "0.1.0+#{sha}"
   end
 end