Fix title position in changelog

Author: fcollonval

CHANGELOG.md

@@ -1,7 +1,5 @@
 # Changes in IPython kernel
 
-## 6.3
-
 <!-- <START NEW CHANGELOG ENTRY> -->
 
 ## 6.6.0
@@ -130,6 +128,8 @@
 
 [@Carreau](https://github.com/search?q=repo%3Aipython%2Fipykernel+involves%3ACarreau+updated%3A2021-08-31..2021-09-09&type=Issues) | [@frenzymadness](https://github.com/search?q=repo%3Aipython%2Fipykernel+involves%3Afrenzymadness+updated%3A2021-08-31..2021-09-09&type=Issues) | [@martinRenou](https://github.com/search?q=repo%3Aipython%2Fipykernel+involves%3AmartinRenou+updated%3A2021-08-31..2021-09-09&type=Issues) | [@minrk](https://github.com/search?q=repo%3Aipython%2Fipykernel+involves%3Aminrk+updated%3A2021-08-31..2021-09-09&type=Issues)
 
+## 6.3
+
 ## 6.3.1
 
 ([Full Changelog](https://github.com/ipython/ipykernel/compare/v6.3.0...0b4a8eaa080fc11e240ada9c44c95841463da58c))