docs: prepare for 2.8.0

Signed-off-by: Henry Schreiner <[email protected]>

Author: henryiii

docs/changelog.md

@@ -2,9 +2,20 @@
 
 ## WIP
 
+## Version 2.8.0
+
+Features:
+
+* Support boost-histogram 1.5; drop support for Python 3.7, add support for
+  Python 3.13 / 3.13t
+  [#582](https://github.com/scikit-hep/hist/pull/582)
+
+Fixes:
+
 * Support IntCat for plot1d overlay
   [#419](https://github.com/scikit-hep/hist/pull/419)
 
+
 ## Version 2.7.3
 
 This release fixes an issue with Python 3.12 pulling in NumPy 2 pre-releases.