do not post any Slack notification

.github/workflows/linux-build.yaml

@@ -5,15 +5,11 @@ jobs:
   build:
     runs-on: [self-hosted, linux, X64]
     steps:
-      - name: Record initial timestamp
-        run: |
-          echo "CI_INITIAL_TIMESTAMP=$(date '+%s')" >> $GITHUB_ENV
       - name: Check out repo        
         uses: actions/checkout@v2
       - name: Identify the base FStar branch and the notification channel
         run: |
           echo "FSTAR_BRANCH=$(jq -c -r '.BranchName' .docker/build/config.json)" >> $GITHUB_ENV
-          echo "CI_SLACK_CHANNEL=$(jq -c -r '.NotificationChannel' .docker/build/config.json)" >> $GITHUB_ENV
       - name: Build Steel and its dependencies
         run: |
           ci_docker_image_tag=steel:local-binary-run-$GITHUB_RUN_ID-$GITHUB_RUN_ATTEMPT
@@ -27,65 +23,3 @@ jobs:
         with:
           name: steel.tar
           path: steel.tar
-      - name: Compute elapsed time
-        if: ${{ always() }}
-        run: |
-          CI_FINAL_TIMESTAMP=$(date '+%s')
-          CI_TIME_DIFF=$(( $CI_FINAL_TIMESTAMP - $CI_INITIAL_TIMESTAMP ))
-          echo "CI_TIME_DIFF_S=$(( $CI_TIME_DIFF % 60 ))" >> $GITHUB_ENV
-          echo "CI_TIME_DIFF_M=$(( ($CI_TIME_DIFF / 60) % 60 ))" >> $GITHUB_ENV
-          echo "CI_TIME_DIFF_H=$(( $CI_TIME_DIFF / 3600 ))" >> $GITHUB_ENV
-          case ${{ job.status }} in
-          (success)
-            echo "CI_EMOJI=✅" >> $GITHUB_ENV
-            ;;
-          (cancelled)
-            echo "CI_EMOJI=⚠" >> $GITHUB_ENV
-            ;;
-          (*)
-            echo "CI_EMOJI=❌" >> $GITHUB_ENV
-            ;;
-          esac
-          echo "CI_COMMIT=$(echo ${{ github.event.head_commit.id || github.event.pull_request.head.sha }} | grep -o '^........')" >> $GITHUB_ENV
-      - name: Post to the Slack channel
-        if: ${{ always() }}
-        id: slack
-        uses: slackapi/[email protected]
-        with:
-          channel-id: ${{ env.CI_SLACK_CHANNEL }}
-          payload: |
-            {
-              "blocks" : [
-                {
-                  "type": "section",
-                  "text": {
-                    "type": "mrkdwn",
-                    "text": "<${{ github.event.head_commit.url || github.event.pull_request.html_url }}|${{ env.CI_COMMIT }}> on (${{ github.ref_name }}) (produce Linux binary) by ${{ github.event.head_commit.author.username || github.event.pull_request.user.login }}"
-                  }
-                },
-                {
-                  "type": "section",
-                  "text": {
-                    "type": "plain_text",
-                    "text": ${{ toJSON(github.event.head_commit.message || github.event.pull_request.title) }}
-                  }
-                },
-                {
-                  "type": "section",
-                  "text": {
-                    "type": "mrkdwn",
-                    "text": "${{ env.CI_EMOJI }} <https://github.com/${{github.repository}}/actions/runs/${{github.run_id}}|${{ job.status }}>"
-                  }
-                },
-                {
-                  "type": "section",
-                  "text": {
-                    "type": "plain_text",
-                    "text": "Duration: ${{ env.CI_TIME_DIFF_H }}h ${{ env.CI_TIME_DIFF_M }}min ${{ env.CI_TIME_DIFF_S }}s"
-                  }
-                }
-              ]
-            }
-        env:
-          SLACK_WEBHOOK_URL: ${{ secrets.SLACK_WEBHOOK_URL }}
-          SLACK_WEBHOOK_TYPE: INCOMING_WEBHOOK