Upgrade `eframe` to 0.30.0

[c-git]

This turned out to be a bigger PR than I planned. But submitted for review as I'd already completed it to the best of my ability. There are open questions that I was unable to answer due to lack of context.

Open questions:

• I wasn't sure how you wanted to deal with the warning about the lints priority and thus didn't do anything about them for now. Lints in question are future_incompatible, nonstandard_style, and rust_2018_idioms in the workspace Cargo.toml
• I updated the index.html from the one in the eframe template and it resulted false positive for lychee. I think it is a false positive because after trunk build the manifest.json is correctly referenced.

Changes made

• Bumped the MSRV to the same as eframe
• Corrected the name of the page in index.html because it was saying table demo
• Upgraded the version of eframe
• Added an allow to stop the clippy lint about unused mut ref because I think it was there to make the API the same between both WASM and Native.
• Ran cargo update because was unable to compile after the MSRV and eframe upgrades without running it.