Fix CI for check-role-prefix script

We're skipping Single quotes in sed as we want
literal $ in the sed pattern, not shell expansion.
Added this file to irrelevant-files.

Author: evallesp

scripts/check-role-prefix.sh

@@ -24,9 +24,9 @@ MSG=$(head -n 1 "$TMP_MSG_FILE")
 ROLE_COUNT=$(echo "$CHANGED_ROLES" | tr '|' '\n' | wc -l)
 
 if [ "$ROLE_COUNT" -eq 1 ]; then
-    # shellcheck disable=SC1087
+    # shellcheck disable=SC2016
     ESCAPED_ROLE=$(printf '%s\n' "$CHANGED_ROLES" | sed 's/[]\.*^$()+?{|]/\\&/g')
-    PATTERN="^[[(]$ESCAPED_ROLE[])]"
+    PATTERN="^[[(]${ESCAPED_ROLE}[])]"
 else
     PATTERN="^[[(](multiple)[])]"
 fi

zuul.d/base.yaml

@@ -53,6 +53,7 @@
       - .pre-commit-config.yaml
       - .readthedocs.yaml
       - .spellcheck.yml
+      - ^scripts/check-role-prefix.sh$
       - roles/dlrn_report
       - roles/dlrn_promote
       - roles/devscripts