cookiecutter: Add cookiecutter sections to RELEASE_NOTES.md

This makes it easier for users to know which changes are code changes
and which are cookiecutter template changes.

Signed-off-by: Leandro Lucarella <[email protected]>

Author: llucax

.github/RELEASE_NOTES.template.md

@@ -8,10 +8,22 @@
 
 <!-- Here goes notes on how to upgrade from previous versions, including deprecations and what they should be replaced with -->
 
+### Cookiecutter template
+
+<!-- Here upgrade steps for cookiecutter specifically -->
+
 ## New Features
 
 <!-- Here goes the main new features and examples or instructions on how to use them -->
 
+### Cookiecutter template
+
+<!-- Here new features for cookiecutter specifically -->
+
 ## Bug Fixes
 
 <!-- Here goes notable bug fixes that are worth a special mention or explanation -->
+
+### Cookiecutter template
+
+<!-- Here bug fixes for cookiecutter specifically -->