docs(changelog): display all sections

Remove the hidden parameter in changelog.yaml for the sections types:
build, ci, docs, perf, refactor, revert, style, test and chore.

Signed-off-by: Yann Gautier <yann.gautier@st.com>
Change-Id: Ie40be9e6b99f9c3e14d55227ea299d6faf977fef
(cherry picked from commit 4a10950a8538b0469e08e95af079fefe9ee5c895)
diff --git a/changelog.yaml b/changelog.yaml
index 9d1c3a9..965ffaa 100644
--- a/changelog.yaml
+++ b/changelog.yaml
@@ -24,47 +24,38 @@
   - title: Build System
     description: Changes that affect the build system or external dependencies
     type: build
-    hidden: true
 
   - title: Continuous Integration
     description: Changes to our CI configuration files and scripts
     type: ci
-    hidden: true
 
   - title: Documentation
     description: Documentation-only changes
     type: docs
-    hidden: true
 
   - title: Performance Improvements
     description: A code change that improves performance
     type: perf
-    hidden: true
 
   - title: Code Refactoring
     description: A code change that neither fixes a bug nor adds a feature
     type: refactor
-    hidden: true
 
   - title: Reverted Changes
     description: Changes that revert a previous change
     type: revert
-    hidden: true
 
   - title: Style
     description: Changes that do not affect the meaning of the code (white-space, formatting, missing semi-colons, etc.)
     type: style
-    hidden: true
 
   - title: Tests
     description: Adding missing tests or correcting existing tests
     type: test
-    hidden: true
 
   - title: Miscellaneous
     description: Any other change
     type: chore
-    hidden: true
 
 #
 # The following block describes the sub-sections of the changelog. These sub-sections may appear in