Support aconfig_declarations, aconfig_values and aconfig_value_set

Bug: 297356603
Test: Unit tests
Change-Id: I2f797578a35322440db0f281b4d46b6652512e00
diff --git a/android/variable.go b/android/variable.go
index 02eff25..3ca7963 100644
--- a/android/variable.go
+++ b/android/variable.go
@@ -475,8 +475,8 @@
 	ProductBrand        string   `json:",omitempty"`
 	BuildVersionTags    []string `json:",omitempty"`
 
-	ReleaseVersion          string   `json:",omitempty"`
-	ReleaseAconfigValueSets []string `json:",omitempty"`
+	ReleaseVersion          string `json:",omitempty"`
+	ReleaseAconfigValueSets string `json:",omitempty"`
 
 	ReleaseAconfigFlagDefaultPermission string `json:",omitempty"`