fix error in app.yml

Signed-off-by: Sebastian Schüpbach <sebastian.schuepbach@unibas.ch>
3 jobs for master in 3 minutes and 43 seconds (queued for 3 seconds)
Name Stage Failure
failed
build-latest-image Publish
See https://docs.gradle.org/6.3/userguide/command_line_interface.html#sec:command_line_warnings

BUILD SUCCESSFUL in 1m 18s
6 actionable tasks: 6 executed
INFO[0110] Taking snapshot of full filesystem...
error building image: error building stage: failed to take snapshot: Failed to get file info for /root/.kotlin/daemon/kotlin-daemon.2021-03-02T10-16-48.231Z.26d08c98e184deac84af38df14ce31be.17438.run: lstat /root/.kotlin/daemon/kotlin-daemon.2021-03-02T10-16-48.231Z.26d08c98e184deac84af38df14ce31be.17438.run: no such file or directory
Running after_script
Uploading artifacts for failed job
ERROR: Job failed: exit code 1