[15.4.7-rc7] use iso8601 in datetime lua helpers

VERSION

@@ -1 +1 @@
-15.4.7-rc6
+15.4.7-rc7

lib/os/lua/info.ex

@@ -84,15 +84,15 @@ defmodule FarmbotOS.Lua.Info do
   def utc(["hour"], lua), do: {[utc_p().hour], lua}
   def utc(["minute"], lua), do: {[utc_p().minute], lua}
   def utc(["second"], lua), do: {[utc_p().second], lua}
-  def utc(_, lua), do: {[DateTime.to_string(utc_p())], lua}
+  def utc(_, lua), do: {[DateTime.to_iso8601(utc_p())], lua}
 
   def local_time(["year"], lua), do: {[local_time_p().year], lua}
   def local_time(["month"], lua), do: {[local_time_p().month], lua}
   def local_time(["day"], lua), do: {[local_time_p().day], lua}
   def local_time(["hour"], lua), do: {[local_time_p().hour], lua}
   def local_time(["minute"], lua), do: {[local_time_p().minute], lua}
   def local_time(["second"], lua), do: {[local_time_p().second], lua}
-  def local_time(_, lua), do: {[DateTime.to_string(local_time_p())], lua}
+  def local_time(_, lua), do: {[DateTime.to_iso8601(local_time_p())], lua}
 
   defp utc_p() do
     DateTime.utc_now()

test/os/lua/ext/info_test.exs

@@ -127,7 +127,7 @@ defmodule FarmbotOS.Lua.InfoTest do
 
   test "utc()" do
     utc = DateTime.utc_now()
-    now = String.slice(DateTime.to_string(utc), 0..15)
+    now = String.slice(DateTime.to_iso8601(utc), 0..15)
     lua_code = "return utc()"
     {:ok, [actual]} = lua(lua_code, lua_code)
     assert String.starts_with?(actual, now)
@@ -171,7 +171,7 @@ defmodule FarmbotOS.Lua.InfoTest do
   test "local_time()" do
     tz = "America/Chicago"
     local = Timex.Timezone.convert(DateTime.utc_now(), tz)
-    now = String.slice(DateTime.to_string(local), 0..15)
+    now = String.slice(DateTime.to_iso8601(local), 0..15)
     lua_code = "return local_time()"
     {:ok, [actual]} = lua(lua_code, lua_code)
     assert String.starts_with?(actual, now)