Correct header styling (#55)

When converting from rst to md, headers were sized larger than needed.
In this PR I am changing headers from ## to ### to correct the styling
issues in readthedocs.

[ reviewed by @AlyssaCote ]
[ committed by @amandarichardsonn ]

Author: amandarichardsonn

doc/changelog.md

@@ -1,9 +1,11 @@
 # Changelog
 
-## Development branch
+### Development branch
 
 Description
 
+-   Fix header styling issue
+    ([SmartDashboard-PR55](https://github.com/CrayLabs/SmartDashboard/pull/55))
 -   Automate the creation of release notes
     ([SmartDashboard-PR54](https://github.com/CrayLabs/SmartDashboard/pull/54))
 -   Add database telemetry documentation.
@@ -24,7 +26,7 @@ Description
 -   Add manifest file tracking.
     ([SmartDashboard-PR46](https://github.com/CrayLabs/SmartDashboard/pull/46))
 
-## 0.0.3
+### 0.0.3
 
 Released on 15 February 2024
 
@@ -35,7 +37,7 @@ Description
 -   Added experiment level logs to the dashboard.
     ([SmartDashboard-PR37](https://github.com/CrayLabs/SmartDashboard/pull/37))
 
-## 0.0.2
+### 0.0.2
 
 Released on 14 December 2023