Pin a devcontainer version to workaround library search path issue

[bpkroth]

A new base devcontainer image was released recently that introduces the following error in our environment when running make test:

 import pandas._libs.window.aggregations as window_aggregations\n'
 'ImportError: /usr/lib/x86_64-linux-gnu/libstdc++.so.6: version '
 "`GLIBCXX_3.4.29' not found (required by "
 '/opt/conda/envs/mlos/lib/python3.11/site-packages/pandas/_libs/window/aggregations.cpython-311-x86_64-linux-gnu.so)\n')

A simplified reproduction involves running conda run -n mlos pytest mlos_bench/mlos_bench/launcher_run_test.ph.

Unfortunately, it appears that under the latest version somewhere between conda and pytest the libc.so.6 library found is the one under /usr/lib instead of /opt/conda/envs/mlos/lib.

I haven't quite seen where that's happening, but I've confirmed that rolling back to the previous release for the base devcontainer image fixes it.

Note that even then, we update conda to the latest and no-cache update our own dependencies nightly, so we are getting the latest conda at least, if not the latest Debian base packages.

This will be somewhat of a security issue eventually, but for now it frees up our CI pipeline to get moving again.