Upgrade to new ember-modifiers syntax

[nickschot]

This resolves the deprecations thrown by ember-modifier

See: https://github.com/ember-modifier/ember-modifier/blob/master/MIGRATIONS.md

[SergeAstapov]

@nickschot I think this should change "ember-modifier": "^3.0.0" in package.json to "ember-modifier": "^3.2.0" as otherwise this change would break apps using ember-modifier v3.1.0 or ember-modifier v3.0.0

Alternatively, this could be both backward and forward compatible with old and new API using @embroider/macros, e.g. like in https://github.com/DockYard/ember-in-viewport/pull/306/files#diff-90b347e9e07bc6b4b1cf6215b21e606557ae635d920b6bb349351912c4473fd1

[nickschot]

@nickschot I think this should change "ember-modifier": "^3.0.0" in package.json to "ember-modifier": "^3.2.0" as otherwise this change would break apps using ember-modifier v3.1.0 or ember-modifier v3.0.0

Alternatively, this could be both backward and forward compatible with old and new API using @embroider/macros, e.g. like in https://github.com/DockYard/ember-in-viewport/pull/306/files#diff-90b347e9e07bc6b4b1cf6215b21e606557ae635d920b6bb349351912c4473fd1

Whoops! Thanks for catching that. I'll fix that by bumping the dependency for now. Will look at the macros fix later.