Add a change log for 0.7.0 (#30)

Signed-off-by: mprahl <mprahl@users.noreply.github.com>

Author: mprahl

CHANGELOG/CHANGELOG-v0.7.0.md

@@ -0,0 +1,9 @@
+# v0.7.0
+
+* Added the `PolicySets` API to logically group policies
+* Added support for the `fromSecret` and `protect` Hub template functions which are used to safely deploy sensitive
+  data to managed clusters
+* Changed the log level flag to `--log-level` and `-v` for library logs
+* Improved logging
+* Improved performance
+* Updated the dependencies