Getting a validation warning for markdeep script

```
./casual-effects.com/markdeep/latest/markdeep.min.js: FAILED
sha256sum: WARNING: 1 computed checksum did NOT match
DANGER: Validation failed for downloaded third-party code; tampered with?
```

It looks like this pulls the latest version, and validates against a checksum, so it will start failing any time a new markdeep is released. We should either pin the version, or stop validating the checksum. Pinning the version is the safer choice, but I suddenly realize this is volunteering me for a pretty tedious job constantly trying to stay up to date with security bugs and such in downstream libraries. That sucks.

Individua la regola per il download e la convalida del checksum di casual-effects.com/markdeep/latest/markdeep.min.js. Verifica come sono definiti l’URL corrente e lo sha256 previsto, quindi blocca la versione dell’artefatto e aggiorna il relativo checksum affinché la convalida abbia esito positivo per il file bloccato.

Scritto dal modello di indicizzazione a partire dal testo della issue.