Use `ubuntu-18.04` for GemStone builds.
Use `ubuntu-18.04` for GemStone builds.
hpi-swa/filetreeCI,hpi-swa/smalltalkCI,hpi-swa/smalltalkCI,fniephaus/filetreeCI,fniephaus/filetreeCI,hpi-swa/filetreeCI,fniephaus/filetreeCI,hpi-swa/filetreeCI