For simplicity, only define the recommended TagBot configuration in a single place?

[DilumAluthge]

Currently, the officially recommended TagBot configuration is located in two places:

1. The "Setup" section of the README.md file
2. The example.yml file

It's a little sub-optimal to have the same information duplicated in two different places. For example, if we make a change in one place, we have to remember to also change the other place; otherwise, the two will become out-of-sync.

When TagBot is re-written in Julia, perhaps we could re-organize it so that we only need to define the recommended TagBot configuration in a single place.

For example, in CompatHelper, we define the recommended TagBot configuration in a single place: https://github.com/JuliaRegistries/CompatHelper.jl/blob/master/.github/workflows/CompatHelper.yml

And then, when we generate the documentation, we automatically pull in the contents of the .github/workflows/CompatHelper.yml file using an @eval block, as such: https://github.com/JuliaRegistries/CompatHelper.jl/blob/master/docs/src/index.md