Update context description to new format

[gmlueck]

Update the section describing the context class to the new format.

[TApplencourt]

THanks will review this week!

[TApplencourt]

May need to re-trigger the CI. Seem like a transcient error to me:

Run actions/create-github-app-token@v1
/home/runner/work/_actions/actions/create-github-app-token/v1/dist/main.cjs:39821
  throw new Error("Input required and not supplied: app-id");
  ^

Error: Input required and not supplied: app-id
    at Object.<anonymous> (/home/runner/work/_actions/actions/create-github-app-token/v1/dist/main.cjs:39821:9)
    at Module._compile (node:internal/modules/cjs/loader:1358:14)
    at Module._extensions..js (node:internal/modules/cjs/loader:1416:10)
    at Module.load (node:internal/modules/cjs/loader:1208:32)
    at Module._load (node:internal/modules/cjs/loader:1024:12)
    at Function.executeUserEntryPoint [as runMain] (node:internal/modules/run_main:174:12)
    at node:internal/main/run_main_module:28:49

Node.js v20.13.1