Clear release notes (#70)

Author: cwasicki

RELEASE_NOTES.md

@@ -6,12 +6,6 @@
 
 ## Upgrading
 
-* Install command line tool as `reporting-cli`: The command line tool from the example is moved
-  to the package and can be called via `reporting-cli` or `python -m frequenz.client.reporting`
-  from the command line.
-* The command-line argument `--display` is renamed to `--format` for `reporting-cli`.
-* The `reporting-cli` tool can output CSV format, dataframe output is removed.
-
 ## New Features
 
 ## Bug Fixes