Fix typo in release notes

Signed-off-by: Mathias L. Baumann <[email protected]>

Author: Marenz

RELEASE_NOTES.md

@@ -20,7 +20,7 @@ This release updates the `frequenz-api-dispatch` dependency to `v1.0.0-rc3` and
 * Support secrets for signing and verifying messages.
   * Use the new env variable `DISPATCH_API_SIGN_SECRET` to set the secret key.
   * Use the new `sign_secret` parameter in the `DispatchClient` constructor to set the secret key.
-* Added `auth_key` parameter to the `dispatch-cli` and thew env variable `DISPATCH_API_AUTH_KEY` to set the authentication key for the Dispatch API.
+* Added `auth_key` parameter to the `dispatch-cli` and the new variable `DISPATCH_API_AUTH_KEY` to set the authentication key for the Dispatch API.
 
 
 ## Bug Fixes