Use `wrangler.toml.example` file in the repo instead of `wrangler.toml`

[zaherg]

Currently, if I cloned the repo and updated the wrangler.toml with the info from my account, this would be considered as a modification for the repo code, so when I try to update the repo in the future, I'll need to stash my changes or commit them before pulling any new changes.

This small change, will introduce wrangler.toml.example which can be used as a template for wrangler.toml, this way any update to the local wrangler.toml file won't have any impact on the update process.

[gabivlj]

thank you so much for the contribution @zaherg <3