Update changelog for 0.51.0 release.

Author: pocmo

docs/changelog.md

@@ -4,14 +4,22 @@ title: Changelog
 permalink: /changelog/
 ---
 
-# 0.51.0-SNAPSHOT  (In Development)
+# 0.52.0-SNAPSHOT  (In Development)
 
-* [Commits](https://github.com/mozilla-mobile/android-components/compare/v0.50.0...master)
-* [Milestone](https://github.com/mozilla-mobile/android-components/milestone/54?closed=1)
+* [Commits](https://github.com/mozilla-mobile/android-components/compare/v0.51.0...master)
+* [Milestone](https://github.com/mozilla-mobile/android-components/milestone/55?closed=1)
 * [Dependencies](https://github.com/mozilla-mobile/android-components/blob/master/buildSrc/src/main/java/Dependencies.kt)
 * [Gecko](https://github.com/mozilla-mobile/android-components/blob/master/buildSrc/src/main/java/Gecko.kt)
 * [Configuration](https://github.com/mozilla-mobile/android-components/blob/master/buildSrc/src/main/java/Config.kt)
 
+# 0.51.0
+
+* [Commits](https://github.com/mozilla-mobile/android-components/compare/v0.50.0...v0.51.0)
+* [Milestone](https://github.com/mozilla-mobile/android-components/milestone/54?closed=1)
+* [Dependencies](https://github.com/mozilla-mobile/android-components/blob/v0.51.0/buildSrc/src/main/java/Dependencies.kt)
+* [Gecko](https://github.com/mozilla-mobile/android-components/blob/v0.51.0/buildSrc/src/main/java/Gecko.kt)
+* [Configuration](https://github.com/mozilla-mobile/android-components/blob/v0.51.0/buildSrc/src/main/java/Config.kt)
+
 * **browser-awesomebar**
   * Fixed an issue where new suggestions would leave you scrolled to the middle of the list