doc: Add changelog entry

Author: effigies

changelog.d/20250807_170325_markiewicz_update_schema.md

@@ -0,0 +1,34 @@
+### Changed
+
+- Upgraded to BIDS schema version 1.0.13.
+
+<!--
+### Fixed
+
+- A bullet item for the Fixed category.
+
+-->
+<!--
+### Deprecated
+
+- A bullet item for the Deprecated category.
+
+-->
+<!--
+### Removed
+
+- A bullet item for the Removed category.
+
+-->
+<!--
+### Security
+
+- A bullet item for the Security category.
+
+-->
+<!--
+### Infrastructure
+
+- A bullet item for the Infrastructure category.
+
+-->