Remove exceptions from deny.toml

The ignored advisory no longer triggers after the jwt-simple upgrade.

The only unmaintained warning we had was for dotenv and an upcoming
version of cargo-deny will always error for unmaintained dependencies
(removing the configuration option) so might as well set it to deny now.

deny.toml

@@ -9,13 +9,10 @@ targets = [
 db-path = "~/.cargo/advisory-db"
 db-urls = ["https://github.com/rustsec/advisory-db"]
 vulnerability = "deny"
-unmaintained = "warn"
+unmaintained = "deny"
 yanked = "deny"
 notice = "warn"
-ignore = [
-    # TODO: Update dependencies that use rsa crate
-    "RUSTSEC-2023-0071",
-]
+ignore = []
 
 [licenses]
 unlicensed = "deny"