Separate XML line for debug or release mode in android manifest

My Android manifest uses different values when debugging and when releasing.

What's the easiest way to differentiate a value for each build type?

When debug:

    <meta-data
        android:name="com.google.android.maps.v2.API_KEY"
        android:value="my-lovely-debug-api-key" />

When release:

    <meta-data
        android:name="com.google.android.maps.v2.API_KEY"
        android:value="my-lovely-release-api-key" />

tia.