Fix __dask_postcompute__() to better preserve type

In Unidata/MetPy#2945, a call to dask's .compute() was causing the
resulting type to be a different Quantity() variant (from pint.util
rather than the parent registry), which resulted in isinstance()
failing. This changes things to use the appropriate type from `self`
rather than hard-coded class names.

1 files changed, 2 insertions, 0 deletions

diff --git a/CHANGES b/CHANGES
index 1cc6b51..1245268 100644
--- a/CHANGES
+++ b/CHANGES
@@ -12,6 +12,8 @@ Pint Changelog
   (PR #1663)
 - Changed frequency to angular frequency in the docs.
   (PR #1668)
+- Fixed Quantity type returned from `__dask_postcompute__`.
+  (PR #1722)
 
 ### Breaking Changes