Switching to the released 1.0 version of gettext (https://hex.pm/packages/gettext) we get following dependency error:
Because your app depends on ex_cldr ~> 2.43.1 which depends on gettext ~> 0.19, gettext ~> 0.19 is required.
So, because your app depends on gettext ~> 1.0, version solving failed.
For now we will switch back to an older version, since 1.0.0 brings almost nothing new to the tablet