org.mockito.runners.MockitoJUnitRunner is now indeed deprecated, you are supposed to use org.mockito.junit.MockitoJUnitRunner instead. As you can see only the package name has changed, the simple name of the class is still MockitoJUnitRunner.
Excerpt from the javadoc of org.mockito.runners.MockitoJUnitRunner:
Moved to
MockitoJUnitRunner, this class will be removed with
Mockito 3