SONAR-13921 Delete upgrade plugin github action

.github/workflows/upgrade-plugins.yml

@@ -1,46 +0,0 @@
-name: Upgrade SonarQube bundled plugins
-on:
-  schedule:
-    # At 9:00 every Monday
-    - cron: "0 9 * * MON"
-
-jobs:
-  upgrade-plugins-job:
-    # prevent job to run on public repository sonarsource/sonarqube (where action sources are not available)
-    if: github.repository == 'sonarsource/sonar-enterprise'
-    runs-on: ubuntu-latest
-    name: Upgrades the version of plugins bundled into SonarQube
-    steps:
-      - uses: actions/checkout@v1
-        with:
-          fetch-depth: 1
-          ref: master
-      - name: Upgrade plugins in build and create JIRA ticket
-        id: upgrade-plugins
-        uses: ./private/github/actions/upgrade-plugins
-        env:
-          GITHUB_ORG_TOKEN: ${{ secrets.GITHUB_ORG_TOKEN }}
-          JIRA_LOGIN: ${{ secrets.JIRA_LOGIN }}
-          JIRA_PASSWORD: ${{ secrets.JIRA_PASSWORD }}
-          REPOX_API_KEY: ${{ secrets.REPOX_API_KEY }}
-        with:
-          build_gradle_path: build.gradle
-      - name: Create Pull Request
-        if: steps.upgrade-plugins.outputs.has_changes == 'true'
-        uses: peter-evans/create-pull-request@v1.5.1
-        env:
-          COMMIT_MESSAGE: ${{ steps.upgrade-plugins.outputs.commit_message }}
-          GITHUB_TOKEN: ${{ secrets.GITHUB_ORG_TOKEN }}
-          PULL_REQUEST_TITLE: ${{ steps.upgrade-plugins.outputs.commit_message }}
-          PULL_REQUEST_BODY: Auto-generated pull request to apply plugin upgrades.
-          PULL_REQUEST_BRANCH: bot/upgrade_plugins
-          PULL_REQUEST_REVIEWERS: wouter-admiraal-sonarsource
-          BRANCH_SUFFIX: timestamp
-          PULL_REQUEST_LABELS: bot
-      - name: Notify failures on Slack
-        if: failure()
-        uses: Ilshidur/action-slack@2.0.0
-        env:
-          SLACK_WEBHOOK: ${{ secrets.SLACK_WEBHOOK }}
-        with:
-          args: "Failed to create a PR for updating plugins, see the logs at https://github.com/SonarSource/sonar-enterprise/actions"