Merge branch 'tomstein-master-fix-duplicate-execution' into 'master'

fix: duplicate execution of program-info-bot

See merge request uni-film-club/programm-info-bot!2

run.sh

@@ -40,6 +40,6 @@ Subject: Programm-Info-Bot
 Content-Type: text/plain; charset=UTF-8
 To: ${TO_MAIL}
 
-$(preview)
+$(PREVIEW_TEXT)
 EOF
 ) | msmtp ${MSMTP_ARGUMENTS} ${TO_MAIL}