Externals Update, master branch (2022.05.17.)

Updated all projects to atlasexternals-2.0.134. The two changes wrt. atlasexternals-2.0.133 are (atlasexternals@2.0.133...2.0.134):

• Updated histgrinder to version 0.1.6 (thanks to @ponyisi);
• Taught AtlasCMake and AtlasLCG how to interpret the contents of /etc/os-release on Linux (for CentOS 9 support, as explained in ATLINFR-4539).

Exceptionally neither full-build or full-unit-tests should be necessary for this. The histgrinder update is only relevant for the tests (which I hope at least one of the CI tests will exercise), and the interpretation of /etc/os-release will be exercised during a "normal build" as well.