Don't use deprecated cmake variable

2 jobs for master in 29 minutes and 27 seconds (queued for 40 minutes and 43 seconds)
Status Job ID Name Coverage
  Build
failed #90942
build_clazy_clang_tidy

00:12:52

passed #90941
linux kf5-qt5 qt5.15

00:16:34

41.0%
 
Name Stage Failure
failed
build_clazy_clang_tidy Build
[ 88%] Built target akonadi_ews_resource
[ 88%] Built target akonadi_imap_resource
make: *** [Makefile:160: all] Error 2
Uploading artifacts for failed job
Uploading artifacts...
WARNING: JUnitTestResults.xml: no matching files
ERROR: No files to upload
Cleaning up file based variables
ERROR: Job failed: exit code 1