Update examples/spark for v1beta3

[bcbroussard]

Small part of #6584.

[nikhiljindal]

Thanks a lot for the PR @bcbroussard
v1beta3 is now the default API version. We can just replace the v1beta1 json files by beta3 ones.
Instead of adding a v1beta3 folder, can you just replace the top level beta1 files?

Thanks!

[nikhiljindal]

You can just delete this field

[bcbroussard]

Thanks, missed that one. Updated.

[bcbroussard]

@nikhiljindal - Sure thing, I was wondering about that, but decided to play it safe and follow the pattern Tim and others were using. Making the updates on my other PR's too

[bcbroussard]

@nikhiljindal - commits squashed, should be ready to go

[nikhiljindal]

LGTM, Thanks!