Make possible to use ETC texture format with GLES3 on Android

Currently, textures are not exported if use ETC on project settings and export project with GLES3.
GLES3 should be able to use ETC format also.

platform/android/export/export.cpp

@@ -1121,9 +1121,10 @@ public:
 			r_features->push_back("etc");
 		else*/
 		String driver = ProjectSettings::get_singleton()->get("rendering/quality/driver/driver_name");
-		if (driver == "GLES2") {
+		if (driver == "GLES2" || driver == "GLES3") {
 			r_features->push_back("etc");
-		} else {
+		}
+		if (driver == "GLES3") {
 			r_features->push_back("etc2");
 		}