fix: upgrade piscina from 4.1.0 to 4.4.0

Snyk has created this PR to upgrade piscina from 4.1.0 to 4.4.0.

See this package in npm:
https://www.npmjs.com/package/piscina

See this project in Snyk:
https://app.snyk.io/org/oslllo.com/project/b5c2bc03-6e77-42c5-acee-678bf639b16c?utm_source=github&utm_medium=referral&page=upgrade-pr

package.json

@@ -49,7 +49,7 @@
     "oslllo-potrace": "^2.0.1",
     "oslllo-svg2": "^2.0.2",
     "oslllo-validator": "^3.1.0",
-    "piscina": "^4.1.0",
+    "piscina": "^4.4.0",
     "yargs": "^16.2.0"
   },
   "devDependencies": {