Releasing 0.9.0 (#3974)

Changelog.md

@@ -1,22 +1,24 @@
 # Motoko compiler changelog
 
+## 0.9.0 (2023-05-12)
+
 * motoko (`moc`)
 
   * **For beta testing:** Add a new _incremental_ GC, enabled with new moc flag `--incremental-gc` (#3837).
     The incremental garbage collector is designed to scale for large program heap sizes.
 
-    The GC distributes its workload across multiple steps, called increments, that each pause the mutator 
-    (user's program) for only a limited amount of time. As a result, the GC work can fit within the instruction-limited 
+    The GC distributes its workload across multiple steps, called increments, that each pause the mutator
+    (user's program) for only a limited amount of time. As a result, the GC work can fit within the instruction-limited
     IC messages, regardless of the heap size and the object structures.
-    
-    According to GC benchmark measurements, the incremental GC is more efficient than the existing copying, compacting, 
+
+    According to GC benchmark measurements, the incremental GC is more efficient than the existing copying, compacting,
     and generational GC in the following regards:
     * Scalability: Able to use the full heap space, 3x more object allocations on average.
     * Shorter interruptions: The GC pause has a maximum limit that is up to 10x shorter.
     * Lower runtimes: The number of executed instructions is reduced by 10% on average (compared to the copying GC).
     * Less GC overhead: The amount of GC work in proportion to the user's program work drops by 10-16%.
-    
-    The GC incurs a moderate memory overhead: The allocated WASM memory has been measured to be 9% higher 
+
+    The GC incurs a moderate memory overhead: The allocated WASM memory has been measured to be 9% higher
     on average compared to the copying GC, which is the current default GC.
 
     To activate the incremental GC under `dfx`, the following command-line argument needs to be specified in `dfx.json`:
@@ -29,6 +31,8 @@
     ...
     ```
 
+  * bugfix: `array.vals()` now returns a working iterator for mutable arrays (#3497, #3967).
+
 ## 0.8.8 (2023-05-02)
 
 * motoko (`moc`)