change: use RFC 9535 syntax for jwt-role-claim-key config

BREAKING CHANGE

Breaks the string comparison operators implemented in #3813. Those can
be replaced with regex searches using JSON Path `search()` function.

Signed-off-by: Taimoor Zaeem <taimoorzaeem@gmail.com>

test/io/configs/no-defaults.config

@@ -22,7 +22,7 @@ db-timezone-enabled = false
 db-tx-end = "rollback-allow-override"
 db-uri = "tmp_db"
 jwt-aud = "https://postgrest.org"
-jwt-role-claim-key = ".user[0].\"real-role\""
+jwt-role-claim-key = "$$.user[0].real_role"
 jwt-secret = "c2VjdXJpdHl0aHJvdWdob2JzY3VyaXR5aW5iYXNlNjQ="
 jwt-secret-is-base64 = true
 jwt-cache-max-entries = 86400