Update CHANGELOG

Author: josevalim

CHANGELOG.md

@@ -90,6 +90,21 @@ As of Elixir v1.12, implicitly decreasing ranges are soft-deprecated and warning
 
 Elixir v1.12 has the additional of many functions across the standard library. The `Enum` module received additions such as `Enum.count_until/2`, `Enum.product/1`, `Enum.zip_with/2`, and more. The `Integer` module now includes `Integer.pow/2` and `Integer.extended_gcd/2`. Finally, the `Kernel` module got two new functions, `Kernel.then/2` and `Kernel.tap/2`, which are specially useful in `|>` pipelines.
 
+## v1.12.1
+
+### 1. Bug fixes
+
+#### Elixir
+
+  * [Code] Make sure `Code.format_string!/2` formats multiline expression inside interpolation on first run
+  * [Macro] Revert keeping of underscores between digits in camelize
+
+#### Mix
+
+  * [Mix] Make sure `Mix.install/2` expand paths for deps
+  * [mix deps.get] Silence false positives on `httpc` warnings
+  * [mix test] Do not run the whole suite when there are no --failed tests as it won't behave as expected inside umbrellas
+
 ## v1.12.0 (2021-05-19)
 
 ### 1. Enhancements