docs: move change log from hypervisor doc

Signed-off-by: Olivier Deprez <olivier.deprez@arm.com>
Change-Id: I486d7d10a65eba23905a7f8eefd47b1a6aa04c1a
diff --git a/docs/index.rst b/docs/index.rst
index ca0714f..1971007 100644
--- a/docs/index.rst
+++ b/docs/index.rst
@@ -8,6 +8,7 @@
    about/index
    design/index
    threat_model_spm
+   change-log
    appendix
 
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