fast-forward-master.sh: Add SSH option to keep accepting ssh-rsa keys

Required with Ubuntu Jammy client. A workaround for
https://linaro.atlassian.net/browse/STG-4216

Signed-off-by: Paul Sokolovsky <paul.sokolovsky@linaro.org>
Change-Id: Idb51685c8fde8c05e407582c6f2910fe915cd952
1 file changed