hasCauseReference() has been introduced in 3.13 (#1443) to support reference comparison.

However, 3.20 introduced cause(), which allows for more flexible assertions, including reference comparison.

Given that the following:

assertThat(exception).hasCauseReference(expected);

can be rewritten as:

assertThat(exception).cause().isSameAs(expected);

we should deprecate hasCauseReference() as it's too specific.