Update instance.ex for web push

lib/mix/tasks/pleroma/instance.ex

@@ -99,6 +99,7 @@ defmodule Mix.Tasks.Pleroma.Instance do
         )
 
       secret = :crypto.strong_rand_bytes(64) |> Base.encode64() |> binary_part(0, 64)
+      {web_push_public_key, web_push_private_key} = :crypto.generate_key(:ecdh, :prime256v1)
 
       result_config =
         EEx.eval_file(
@@ -111,7 +112,9 @@ defmodule Mix.Tasks.Pleroma.Instance do
           dbuser: dbuser,
           dbpass: dbpass,
           version: Pleroma.Mixfile.project() |> Keyword.get(:version),
-          secret: secret
+          secret: secret,
+          web_push_public_key: Base.url_encode64(web_push_public_key, padding: false),
+          web_push_private_key: Base.url_encode64(web_push_private_key, padding: false)
         )
 
       result_psql =