CHANGELOG.md in microgem-1.0.20 vs CHANGELOG.md in microgem-1.0.21

@@ -1,6 +1,10 @@
 ## CHANGELOG
 
+### 1.0.21
+
+* Use frozen strings in generated Ruby files
+
 ### 1.0.20
 
 * travis.yml: Update Rubies, add 2.7
 
 ### 1.0.19