Adapt exception handling logic in CFTimeIndex.__sub__ and __rsub__

The latest version of pandas raises an OutOfBoundsTimedelta error instead
of an Overflow error.

xarray/coding/cftimeindex.py

@@ -59,6 +59,12 @@
 REPR_ELLIPSIS_SHOW_ITEMS_FRONT_END = 10
 
 
+if LooseVersion(pd.__version__) > LooseVersion("1.2.3"):
+    OUT_OF_BOUNDS_TIMEDELTA_ERROR = pd.errors.OutOfBoundsTimedelta
+else:
+    OUT_OF_BOUNDS_TIMEDELTA_ERROR = OverflowError
+
+
 def named(name, pattern):
     return "(?P<" + name + ">" + pattern + ")"
 
@@ -562,7 +568,7 @@ def __sub__(self, other):
         elif _contains_cftime_datetimes(np.array(other)):
             try:
                 return pd.TimedeltaIndex(np.array(self) - np.array(other))
-            except OverflowError:
+            except OUT_OF_BOUNDS_TIMEDELTA_ERROR:
                 raise ValueError(
                     "The time difference exceeds the range of values "
                     "that can be expressed at the nanosecond resolution."
@@ -573,7 +579,7 @@ def __sub__(self, other):
     def __rsub__(self, other):
         try:
             return pd.TimedeltaIndex(other - np.array(self))
-        except OverflowError:
+        except OUT_OF_BOUNDS_TIMEDELTA_ERROR:
             raise ValueError(
                 "The time difference exceeds the range of values "
                 "that can be expressed at the nanosecond resolution."