Pass platform version name as --version-name for framework-res.apk

framework-res.apk should get the platform version name ("9") as
--version-name, not the SDK version ("28").  It will get copied
to compileSdkVersionCodename in APKs compiled against it.

Bug: 78324052
Test: aapt dump badging $OUT/system/framework/framework-res.apk | grep -i version
Change-Id: I34a601cb2c14f66199066e7d598862108da0b950

android/variable.go

@@ -127,6 +127,7 @@ type productVariables struct {
 	BuildNumberFromFile *string `json:",omitempty"`
 	DateFromFile        *string `json:",omitempty"`
 
+	Platform_version_name             *string  `json:",omitempty"`
 	Platform_sdk_version              *int     `json:",omitempty"`
 	Platform_sdk_codename             *string  `json:",omitempty"`
 	Platform_sdk_final                *bool    `json:",omitempty"`