Comment 1 for bug 1988217

https://salsa.debian.org/squid-team/squid/-/commit/c88ab9c5a4239dbf583f31570239a2597680f88c added -Wno-error=deprecated-declarations to d/rules, but didn't replicate the change to d/t/upstream-test-suite.

Either way, we don't need to silence this error anymore because it's been fixed upstream by https://github.com/squid-cache/squid/commit/617ce5838aa6bcb437b3f9ecc8bbfb5c17c44ee2.