Update release notes for 0.4.2

Author: echarles

CHANGELOG.md

@@ -2,7 +2,7 @@
 
 <!-- <START NEW CHANGELOG ENTRY> -->
 
-## 0.4.1
+## 0.4.2
 
 ([Full Changelog](https://github.com/jupyter/nbclassic/compare/v0.4.0...ab19ce1f648c99a0cf847cf9878f1828bedbb9a8))
 
@@ -26,6 +26,10 @@
 
 <!-- <END NEW CHANGELOG ENTRY> -->
 
+## 0.4.1
+
+This release has been skipped by the release process.
+
 ## 0.4.0
 
 ([Full Changelog](https://github.com/jupyter/nbclassic/compare/v0.3.7...b00324a5a3b20ac58e074460050c28a8bcb876bb))