2 gantt demo diagrams fail in Firefox 105.0.3 (64-bit)

[weedySeaDragon]

Describe the bug
2 of the diagrams in demos/gantt.html are now throwing Syntax errors when running using a local dev server (e.g. pnpm dev) and Firefox 105.0.3 (64-bit) [macOs] (just released Oct 7).

The diagrams work fine in Chrome and on the Mermaid live editor.

To Reproduce
Steps to reproduce the behavior:

1. Run a dev server (e.g. pnpm dev)
2. Open the gantt demo page (http://localhost:9000/gantt.html) in that version of Firefox.

The charts titled "Hide today marker" and "Style today marker" are throwing the errors.

Expected behavior
These worked before in prior versions of Firefox.

Desktop (please complete the following information):

• OS: macOS
• Browser Firefox
• Version 105.0.3 (64-bit)

Mermaid develop branch v. 9.2.0-rc2

Additional context
Add any other context about the problem here.

This version of Firefox was released on Oct 7th, which explains why the diagrams worked up until recently. This is the first time I've viewed them since I updated to this version.

[isinek]

It seems that this can be solved by using dateFormat Z and value like -01:00.