Update the Envoy Mobile docs publishing to the envoymobile.io site

[fredyw]

The https://envoymobile.io/ is still reading docs from the old the https://github.com/envoyproxy/envoy-mobile. This needs to be fixed.

[phlax]

thanks for the reminder

i have the dns setup so that we switch over to mobile.envoyproxy.io just havent got round to updating it

[github-actions]

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