ci(workflows): remove welcome-bot (#595)

.github/workflows/welcome-bot.yml

@@ -1,35 +0,0 @@
-# This workflow is hosted at: https://github.com/mdn/workflows/blob/main/.github/workflows/allo-allo.yml
-# Docs for this workflow: https://github.com/mdn/workflows/blob/main/README.md#allo-allo
-name: "AlloAllo"
-
-on:
-  issues:
-    types:
-      - opened
-  pull_request_target:
-    branches:
-      - main
-    types:
-      - opened
-      - closed
-
-jobs:
-  allo-allo:
-    uses: mdn/workflows/.github/workflows/allo-allo.yml@main
-    with:
-      target-repo: "mdn/webextensions-examples"
-      issue-welcome: >
-        It looks like this is your first issue. Welcome! 👋
-        One of the project maintainers will be with you as soon as possible. We
-        appreciate your patience. To safeguard the health of the project, please
-        take a moment to read our [code of conduct](../blob/main/CODE_OF_CONDUCT.md).
-      pr-welcome: >
-        It looks like this is your first pull request. 🎉
-        Thank you for your contribution! One of the project maintainers will triage
-        and assign the pull request for review. We appreciate your patience. To
-        safeguard the health of the project, please take a moment to read our
-        [code of conduct](../blob/main/CODE_OF_CONDUCT.md).
-      pr-merged: >
-        Congratulations on your first merged pull request. 🎉 Thank you for your contribution!
-        Did you know we have a [project board](https://github.com/orgs/mdn/projects/25) with high-impact contribution opportunities?
-        We look forward to your next contribution.