Add changelog sections for post-0.10 development (#965)

CHANGELOG.md

@@ -1,5 +1,23 @@
 # Change Log
 
+## [HEAD](https://github.com/stellargraph/stellargraph/tree/HEAD)
+
+[Full Changelog](https://github.com/stellargraph/stellargraph/compare/v0.10.0...HEAD)
+
+### Major features and improvements
+
+- New algorithms:
+
+### Breaking changes
+
+### Experimental features
+
+Some new algorithms and features are still under active development, and are available as an experimental preview. However, they may not be easy to use: their documentation or testing may be incomplete, and they may change dramatically from release to release. The experimental status is noted in the documentation and at runtime via prominent warnings.
+
+### Bug fixes and other changes
+
+- DevOps changes:
+
 ## [0.10.0](https://github.com/stellargraph/stellargraph/tree/v0.10.0)
 
 [Full Changelog](https://github.com/stellargraph/stellargraph/compare/v0.9.0...v0.10.0)