Update index.rst

Author: rsmontero

source/intro_release_notes/release_notes/index.rst

@@ -10,7 +10,7 @@ Release Notes |version|
    What's New <whats_new>
    Platform Notes <platform_notes>
    Secondary Platforms <secondary>
-   Beta Release of ARM64 packages <arm64_beta>
+   ARM64 packages <arm64>
    Compatibility Guide <compatibility>
    Known Issues <known_issues>
    Acknowledgements <acknowledgements>