tests: Update to catch.hpp v2.13.4 and fix #2178

tests: Update to catch.hpp v2.13.4 and fix #2178

This patch is about fixing a compilation error that we are seeing on
Fedora Rawhide with glibc 2.33.9000, which makes MINSIGSTKSZ not be a
constant value anymore.  Thus, the sigStackSize variable that is
declared constexpr cannot use that MINSIGSTKSZ as initializer anymore.

So as suggested in the issue
https://github.com/catchorg/Catch2/issues/2178 filed against
'catchorg' for this purpose, I am hardwiring the initialization value
of sigStackSize for now.

	* tests/lib/catch.hpp: Update to v2.13.4 and initialize
	sigStackSize to 32768 for now, as suggested by
	https://github.com/catchorg/Catch2/issues/2178.

Signed-off-by: Dodji Seketeli <dodji@redhat.com>