fix: document proper Bison version requirement

fix: document proper Bison version requirement

The minimum version of Bison was bumped to 2.5 a while ago, update the
documentation and help messages that still refer to 2.4.

Change-Id: I3daef3eb51f24ff0194c43e3e13575eaa6de4f56
Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Reviewed-on: https://review.lttng.org/c/babeltrace/+/9734
Tested-by: jenkins <jenkins@lttng.org>
Reviewed-by: Philippe Proulx <eeppeliteloop@gmail.com>
Reviewed-on: https://review.lttng.org/c/babeltrace/+/9884
CI-Build: Simon Marchi <simon.marchi@efficios.com>