docs: Update changelog with unreleased changes (#3263)

Adds unreleased changes to the CHANGELOG to make it easier when doing
the next release.

---------

Signed-off-by: Ian Lewis <ianlewis@google.com>

CHANGELOG.md

@@ -9,6 +9,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 <!-- toc -->
 
+- [Unreleased](#unreleased)
+  - [Unreleased: Gradle Builder](#unreleased-gradle-builder)
+  - [Unreleased: Go Builder](#unreleased-go-builder)
+  - [Unreleased: Container Generator](#unreleased-container-generator)
 - [v1.9.0](#v190)
   - [v1.9.0: BYOB framework (beta)](#v190-byob-framework-beta)
   - [v1.9.0: Maven builder (beta)](#v190-maven-builder-beta)
@@ -93,6 +97,23 @@ Use the format "X.Y.Z: Go builder" etc. for format headers to avoid header name
 duplication."
 -->
 
+## Unreleased
+
+### Unreleased: Gradle Builder
+
+- The Gradle Builder was fixed when the project root is the same as the
+  repository root (#2727)
+
+### Unreleased: Go Builder
+
+- The `go-version-file` input was fixed so that it can find the `go.mod` file
+  (#2661)
+
+### Unreleased: Container Generator
+
+- A new `provenance-repository` input was added to allow reading provenance from
+  a different container repository than the image itself (#2956)
+
 ## v1.9.0
 
 Release [v1.9.0] includes bug fixes and new features.