In https://github.com/open-telemetry/opentelemetry-specification/pull/3678 it was decided that it must be possible to add links to spans after they have been created. However, the [`Span` class](https://github.com/open-telemetry/opentelemetry-python/blob/da48e0b131ff34ff382b7d1206f71b2e31929cab/opentelemetry-sdk/src/opentelemetry/sdk/trace/__init__.py#L712) currently does not provide such an `add_link()` method. Please implement the `Span.add_link()` method as per updated specification. Thank you! 
In open-telemetry/opentelemetry-specification#3678 it was decided that it must be possible to add links to spans after they have been created. However, the
Spanclass currently does not provide such anadd_link()method.Please implement the
Span.add_link()method as per updated specification. Thank you!