TST: Ignore leap second warning

Author: pllim

setup.cfg

@@ -50,6 +50,7 @@ filterwarnings =
     ignore::astropy.io.votable.exceptions.W49
     ignore::astropy.io.votable.exceptions.W21
     ignore::astropy.io.votable.exceptions.W42
+    ignore:leap-second auto-update failed:astropy.utils.exceptions.AstropyWarning
     ignore:numpy.ndarray size changed:RuntimeWarning
     ignore:OverflowError converting::astropy
 # Upstream, remove when fixed, PRs have been opened