message: Update doxygen to `1.9.4`
diff: @@ -32,6 +32,6 @@ debs:
  docker_debs:
  - docker-ce-cli
  -doxygen_ver: "1.9.3"
  +doxygen_ver: "1.9.4"
  doxygen_bin: "doxygen-{{ doxygen_ver }}.linux.bin.tar.gz"
  doxygen_url: "https://doxygen.nl/files/{{ doxygen_bin }}"
  