Align with @ onChanges syntax

[toddmotto]

From the docs:

Called whenever one-way (<) or interpolation (@) bindings are updated. The

• changesObj is a hash whose keys are the names of the bound properties that have changed, and the values are an
• object of the form { currentValue, previousValue, isFirstChange() }. Use this hook to trigger updates within a
• component such as cloning the bound value to prevent accidental mutation of the outer value.