ci: add check for no CRLF line endings.

.github/ci/crlf.sh

@@ -0,0 +1,17 @@
+#!/bin/bash
+## on push branch~=gh-readonly-queue/main/.*
+## on pull_request
+
+set -euo pipefail
+
+FILES_WITH_CRLF=$(find  ! -path "./.git/*" -not -type d | xargs file -N | (grep " CRLF " || true))
+
+if [ -z "$FILES_WITH_CRLF" ]; then
+  echo -e "No files with CRLF endings found."
+  exit 0
+else
+  NR_FILES=$(echo "$FILES_WITH_CRLF" | wc -l)
+  echo -e "ERROR: Found ${NR_FILES} files with CRLF endings."
+  echo "$FILES_WITH_CRLF"
+  exit "$NR_FILES"
+fi