docs(changelog): update errata-abi topic

This has changed from errata_abi to errata-abi. This change was part of:
5c8fcc0ca7f5 ("fix(errata-abi): fix the rev-var for Cortex-A710")

Signed-off-by: Yann Gautier <yann.gautier@st.com>
Change-Id: I2c3f9e6ed07307b8372b5a84a96fbbcfe482a9be
1 file changed