update to latest version of libprov

Recently, we saw a failure in openssl tests when building gost-engine:
https://github.com/openssl/openssl/actions/runs/14192630435/job/39768534802

It occurs because a gost-engine dependency (libprov) requires a minimum
cmake version of 3.0.  Recent distro updates have moved to cmake 4.0,
which error out if a CMakeLists.txt file requires a version less than
3.5.

The libprov tree has been updated to require 3.18 now (matching the
requirement for gost-engine), so we need to update the libprov submodule
here to pull that update in.

diff --git a/libprov b/libprov
index 8a126e09547630ef900177625626b6156052f0ee..0b445c73ae1e87577430c6884cdeeca1afa36dbd 160000 (submodule)
--- a/libprov
+++ b/libprov
@@ -1 +1 @@
-Subproject commit 8a126e09547630ef900177625626b6156052f0ee
+Subproject commit 0b445c73ae1e87577430c6884cdeeca1afa36dbd