🧹 Upgrade pyinstaller (#6011)

The `pyinstaller` package at the given version didn't install on my specific Python version. I bumped the version to the latest and everything seems fine now 🤷. Can't hurt.

**How to test**

We will see if the offline hedy build succeeds.

requirements.txt

@@ -32,7 +32,7 @@ email-validator==2.1.0.post1
 doit==0.36.0
 doit_watch>=0.1.0
 uflash>=2.0.0
-pyinstaller==6.3.0
+pyinstaller==6.11.1
 pylint==3.1.0
 commonmark==0.9.1
 colorama==0.4.6