Set different signing configs with multiple flavors and dimensions

build.gradle

signingConfigs {
	vanillaPaid {
		...
	}
	vanillaFree {
		...
	}
	chocolatePaid {
		...
	}
	chocolateFree {
		...
	}
}

flavorDimensions "taste", "type"

productFlavors {
	vanilla {
		dimension "taste"
		applicationIdSuffix ".vanilla"
	}
	chocolate {
		dimension "taste"
		applicationIdSuffix ".chocolate"
	}
	free {
		dimension "type"
		...
	}
	paid {
		dimension "type"
		...
	}
}

applicationVariants.all { variant ->
	if (variant.name.equals("vanillaPaidRelease")) {
		variant.mergedFlavor.setSigningConfig(signingConfigs.vanillaPaid)
	} else if (variant.name.equals("vanillaFreeRelease")) {
		variant.mergedFlavor.setSigningConfig(signingConfigs.vanillaFree)
	} else if (variant.name.equals("chocolatePaidRelease")) {
		variant.mergedFlavor.setSigningConfig(signingConfigs.chocolatePaid)
	} else if (variant.name.equals("chocolateFreeRelease")) {
		variant.mergedFlavor.setSigningConfig(signingConfigs.chocolateFree)
	}
}

buildTypes {
	release {
		...
	}
	debug {
		...
	}
}