Include "skimage" as filtered module again in warning filter

I'm not exactly sure why this is necessary to catch "skimage" too. Maybe
some part of the implementation raises the warning internally and
doesn't catch it. At the worst, this means users might see a warning
twice. I don't really care enough to investigate because we are
removing the whole thing.

Author: lagru

pyproject.toml

@@ -188,7 +188,7 @@ xfail_strict = true
 testpaths = ["src", "tests"]
 filterwarnings = [
     "error",
-    "ignore:.*use `imageio` or other I/O packages directly.*:FutureWarning:tests",
+    "ignore:.*use `imageio` or other I/O packages directly.*:FutureWarning:(tests|skimage)",
     "ignore:Implicit conversion of A to CSR:scipy.sparse.SparseEfficiencyWarning"  # warn by pyamg in ruge_stuben_solver
 ]
 norecursedirs = ["io/_plugins"]