fix doctests: supress urllib3 warning (pydata#7326)

Author: mathause

xarray/tests/__init__.py

@@ -35,6 +35,8 @@
 except ImportError:
     pass
 
+# https://github.com/pydata/xarray/issues/7322
+warnings.filterwarnings("ignore", "'urllib3.contrib.pyopenssl' module is deprecated")
 
 arm_xfail = pytest.mark.xfail(
     platform.machine() == "aarch64" or "arm" in platform.machine(),