vagrant: netbsd: test on py311 only

the netbsd vagrant machine tends to segfault, guess due to some kernel or virtualbox issue.

 thus, rather only do 1 tox run, so there is less output to review.

Vagrantfile

@@ -93,15 +93,13 @@ def packages_netbsd
     pkg_add pkg-config
     # pkg_add fuse  # llfuse supports netbsd, but is still buggy.
     # https://bitbucket.org/nikratio/python-llfuse/issues/70/perfuse_open-setsockopt-no-buffer-space
-    pkg_add python38 py38-sqlite3 py38-pip py38-virtualenv py38-expat
-    pkg_add python39 py39-sqlite3 py39-pip py39-virtualenv py39-expat
-    pkg_add py310-sqlite3 py310-pip py310-virtualenv py310-expat
-    ln -s /usr/pkg/bin/python3.9 /usr/pkg/bin/python
-    ln -s /usr/pkg/bin/python3.9 /usr/pkg/bin/python3
-    ln -s /usr/pkg/bin/pip3.9 /usr/pkg/bin/pip
-    ln -s /usr/pkg/bin/pip3.9 /usr/pkg/bin/pip3
-    ln -s /usr/pkg/bin/virtualenv-3.9 /usr/pkg/bin/virtualenv
-    ln -s /usr/pkg/bin/virtualenv-3.9 /usr/pkg/bin/virtualenv3
+    pkg_add py311-sqlite3 py311-pip py311-virtualenv py311-expat
+    ln -s /usr/pkg/bin/python3.11 /usr/pkg/bin/python
+    ln -s /usr/pkg/bin/python3.11 /usr/pkg/bin/python3
+    ln -s /usr/pkg/bin/pip3.11 /usr/pkg/bin/pip
+    ln -s /usr/pkg/bin/pip3.11 /usr/pkg/bin/pip3
+    ln -s /usr/pkg/bin/virtualenv-3.11 /usr/pkg/bin/virtualenv
+    ln -s /usr/pkg/bin/virtualenv-3.11 /usr/pkg/bin/virtualenv3
   EOF
 end