Update CHANGELOG.md
New changelog entries should be in 2021 now
# CHANGELOG
-## 3.11.2 - 2020-01-27
+## 3.11.2 - 2021-01-27
- Fixed JSON gem `:decimal_class` option.
-## 3.11.1 - 2020-01-24
+## 3.11.1 - 2021-01-24
- XrXr fixed Ruby 3.0.0 object movement issue.
-## 3.11.0 - 2020-01-12
+## 3.11.0 - 2021-01-12
- Added `:compat_bigdecimal` to support the JSON gem `:decimal_class` undocumented option.
