Externals Update, main branch (2023.08.15.)

Updated all projects to atlasexternals-2.0.165. The changes wrt. atlasexternals-2.0.164 are (atlasexternals@2.0.164...2.0.165):

• Added the -march=x86-64-v2 compilation flag by default on all x86_64 platforms with GCC and Clang (thanks to @smh, addressing ATLINFR-4956);
• Added PyYAML to PyAnalysis, to make it available to AnalysisBase(Externals) (addressing ATLINFR-4882).

The addition of PyYAML is harmless, and as long as the CI manages to build that external (it should...), it should not make a difference for anything right now. But the x86-64-v2 flag could possibly cause changes in some of our tests if we're unlucky. So let's run a full suite of tests. 🤞

Finally note that this MR should be followed by a cleanup of the CI nodes.