Support using env vars for macOS notarization even if a macOS config …

…exists.

Currently there is another related bug in the schema parsing that doesn't allow
actually specifying the notarization authentication parameters in the package metadata
of Cargo.toml, so this change is actually the only way to currently use the notarization
features on macOS.

crates/packager/src/package/app/mod.rs

@@ -158,6 +158,7 @@ pub(crate) fn package(ctx: &Context) -> crate::Result<Vec<PathBuf>> {
  m.notarization_credentials
  .clone()
  .ok_or_else(|| crate::Error::MissingNotarizeAuthVars)
+ .or_else(|_| codesign::notarize_auth())
  })
  .unwrap_or_else(codesign::notarize_auth)
  {