CHANGELOG: Fix formatting
CHANGELOG: Fix formatting

Since release v2.4.0 the indentation of the release headings is wrong.
So fix the indentation for all releases since then.

Closes: https://github.com/ibm-s390-tools/s390-tools/pull/81
Signed-off-by: Michael Holzheu <17b9e1c64588c7fa6419b4d29dc1f4426279ba01@holzheu.de>
Signed-off-by: Jan Höppner <96138615ab4af0813785fa10d283f3d37eca3b78@linux.ibm.com>

ibm-s390-tools/s390-tools,ibm-s390-tools/s390-tools,ibm-s390-tools/s390-tools,ibm-s390-tools/s390-tools