package version metadata for external/

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Change-Id: I0a238923bad3aae67c046d3a871f74f46f547049
diff --git a/README.version b/README.version
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index 0000000..220cddb
--- /dev/null
+++ b/README.version
@@ -0,0 +1,2 @@
+URL: http://downloads.xiph.org/releases/opus/opus-1.1.tar.gz
+Version: 1.1