fix: ruleset path for Example Object validation

[johlo]

The example field has Any values in all contexts
it can be used so the rule should not be triggered for that field.

The examples field always has values of Example Object type in
all contexts, so this is what the rule should trigger on.
And since the examples field takes a map of example objects
the JSON path expression needs the final .* to work.

Updated the tests to validate examples field instead of example and added
one test.

Checklist

• Tests added / updated
• Docs added / updated

Does this PR introduce a breaking change?

• Yes
• No

[nulltoken]

@johlo Looks pretty cool, thanks!

Next to the newly added test validate multiple valid examples, would you mind adding some additional ones to cover the following use cases?

• multiple examples with one of them exposing both value and externalValue
• multiple examples with one of them exposing neither value nor externalValue

[johlo]

* multiple examples with one of them exposing both `value` and `externalValue`

* multiple examples with one of them exposing neither `value` nor `externalValue`

Done, amended to the old commit.

[johlo]

btw, when preparing this PR I've only run the yarn test.prod tests, I couldn't run yarn test.harness since yarn build.binary fails to build the binary (because I'm using node 13.5?).

[nulltoken]

Done, amended to the old commit.

@johlo 👍

@P0lip Could you please take a look?

[P0lip]

Thanks!