Update octool to use python3-pytest instead of nose2

Author: linas

opencog/base/Dockerfile

@@ -37,7 +37,7 @@ RUN apt-get -y install openssh-client
 # Install ocpkg. Bump the date to get the latest ocpkg installed;
 # Otherwise, this docker build will be cached with an old octool.
 # And with the old versions of those packages that octool installs.
-ENV LAST_OCPKG_UPDATE=2025-10-23
+ENV LAST_OCPKG_UPDATE=2025-11-19
 
 # The OCPKG_URL can be overridden by specifying
 # docker build --build-arg OCPKG_URL=https://some.where.else.com/ockpg