Update changelog for #1 and #2

changelog.md

@@ -1,5 +1,10 @@
 # Changelog
 
+# 0.13.0
+
+- Create crate as fork of `shared_memory` crate
+- Add support for read-only mapping
+
 # 0.12.5
 - Update dependencies
 - Use minimal features for `nix` on unix systems
@@ -21,4 +26,4 @@
 # __0.11.X__
 This release breaks backwards compatibility and removes a bunch of previous features which hid many unsafe behaviors (automatically casting shared memory to Rust types).
 
-The release also marks the split between `shared_memory` and its synchronization primitives into a seperate crate `raw_sync`.
+The release also marks the split between `shared_memory` and its synchronization primitives into a seperate crate `raw_sync`.