doc: add -it to docker command for running trivy

It makes the progress bar display correctly.

Author: rouilj

RELEASE.txt

@@ -236,7 +236,7 @@ Roundup release checklist:
 
      Also can scan (optionally) using trivy:
 
-        docker run --rm --volume \
+        docker run -it --rm --volume \
 	/var/run/docker.sock:/var/run/docker.sock \
           --name trivy aquasec/trivy:latest image rounduptracker/roundup:2.2.0