Suppress cargo audit failure for difference crate, there's no newer crate to upgrade to yet

(cherry picked from commit 3eaa826ad9)

ci/test-checks.sh

@@ -80,6 +80,12 @@ cargo_audit_ignores=(
   #
   # Blocked on multiple crates updating `time` to >= 0.2.23
   --ignore RUSTSEC-2020-0071
+
+  # difference is unmaintained
+  #
+  # Blocked on predicates v1.0.6 removing its dependency on `difference`
+  --ignore RUSTSEC-2020-0095
+
 )
 _ scripts/cargo-for-all-lock-files.sh +"$rust_stable" audit "${cargo_audit_ignores[@]}"