fix(scripts): set CI=true in pre-push hook

This enables -Werror

Author: msfjarvis

scripts/pre-push-hook.sh

@@ -13,6 +13,6 @@ while read -r local_ref local_oid remote_ref remote_oid; do
   _=$remote_ref
   _=$remote_oid
   if [ "${local_oid}" != "${ZERO}" ]; then
-    "${GRADLE_EXEC}" metalavaCheckCompatibilityRelease lint ktfmtCheck test -PslimTests
+    CI=true "${GRADLE_EXEC}" metalavaCheckCompatibilityRelease lint ktfmtCheck test -PslimTests
   fi
 done