Fix postgres port in CI

.drone.yml

@@ -55,6 +55,7 @@ steps:
     environment:
       MIX_ENV: test
       TEST_POSTGRES_HOST: postgres
+      TEST_POSTGRES_PORT: 5432
     commands:
       # Install hex package manager
       - mix local.hex --force

config/test.exs

@@ -9,7 +9,7 @@ config :mv, Mv.Repo,
   username: "postgres",
   password: "postgres",
   hostname: System.get_env("TEST_POSTGRES_HOST", "localhost"),
-  port: 5000,
+  port: System.get_env("TEST_POSTGRES_PORT", 5000),
   database: "mv_test#{System.get_env("MIX_TEST_PARTITION")}",
   pool: Ecto.Adapters.SQL.Sandbox,
   pool_size: System.schedulers_online() * 2