UltraHDR: update Version handling.

Version is now a string as spec'd, and identifier is added to Primary
image XMP to indicate presence of a gain map.

Bug: 278784125
Test: tests pass
Change-Id: Ia76879ca3d187edb78927ad5bab79fc8eef07da8
(cherry picked from commit 4ac2a268cbd211389d7f1d27853b8eeb6f956b72)
diff --git a/libs/ultrahdr/tests/jpegr_test.cpp b/libs/ultrahdr/tests/jpegr_test.cpp
index ba3b4d0..58cd8f4 100644
--- a/libs/ultrahdr/tests/jpegr_test.cpp
+++ b/libs/ultrahdr/tests/jpegr_test.cpp
@@ -180,6 +180,7 @@
 
 TEST_F(JpegRTest, writeXmpThenRead) {
   ultrahdr_metadata_struct metadata_expected;
+  metadata_expected.version = "1.0";
   metadata_expected.maxContentBoost = 1.25;
   metadata_expected.minContentBoost = 0.75;
   const std::string nameSpace = "http://ns.adobe.com/xap/1.0/\0";
@@ -538,7 +539,7 @@
 
   JpegRBenchmark benchmark;
 
-  ultrahdr_metadata_struct metadata = { .version = 1,
+  ultrahdr_metadata_struct metadata = { .version = "1.0",
                               .maxContentBoost = 8.0f,
                               .minContentBoost = 1.0f / 8.0f };