Prepare for v2 release (#232)

* add changelog

* prepare v2

CHANGELOG.md

@@ -0,0 +1,13 @@
+# Changelog
+
+All notable changes to this project will be documented in this file.
+
+### [v2](https://github.com/jrouly/scalafmt-native-action/releases/tag/v2) (2021-03-25)
+
+* Upgrades default `scalafmt` version to [3.5.8](https://github.com/scalameta/scalafmt/releases/tag/v3.5.8).
+  * Note: this version of `scalafmt` may require a version parameter in `.scalafmt.conf`.
+* Various security patches.
+
+### [v1](https://github.com/jrouly/scalafmt-native-action/releases/tag/v1) (2021-03-25)
+
+Initial release.

README.md

@@ -14,7 +14,7 @@ By using the native image, this action typically completes in two to three secon
 ## Usage
 
 ```yaml
-- uses: jrouly/scalafmt-native-action@v1
+- uses: jrouly/scalafmt-native-action@v2
   with:
     # Optional: Which version of scalafmt-native to use.
     # Default: 3.5.8
@@ -32,7 +32,7 @@ If any non-conforming files are present, they will be printed and the command wi
 Otherwise it will silently exit with success.
 
 ```yaml
-- uses: jrouly/scalafmt-native-action@v1
+- uses: jrouly/scalafmt-native-action@v2
 ```
 
 #### OS compatibility