conanfile.txt needs update for conan 0.52

Building arrow with the latests conan in the ubuntu 18.04-based containers requires change in options in conanfile.txt

added Build System Testing labels

assigned to @lukas

created branch 535-conanfile-txt-needs-update-for-conan-0-52 to address this issue

mentioned in merge request !453 (merged)

mentioned in commit 7fad8b78

closed with merge request !453 (merged)