Update sphinx_rtd_theme to 68a19ca / 0.4.3.dev0.

[Chris Johns]

On 26/2/20 3:03 pm, Amar Takhar wrote:
> On 2020-02-26 13:59 +1100, Chris Johns wrote:
>>
>> Does this work on sync.rtems.org with a suitable virtualenv?
>>
>> This is how I build the online docs. :)
> 
> Shouldn't be an issue at all it's in-source no new dependencies.  Try the patch 
> and see if it works? :)  Works here!

Great, I am OK with the patch being pused. If it breaks on sync it will show in
the build not updating and I am sure we can sort it out.

Chris