chore: update github actions [no ci]

Author: svc-cli-bot

.github/workflows/failureNotifications.yml

@@ -13,7 +13,7 @@ jobs:
     steps:
       - name: Announce Failure
         id: slack
-        uses: slackapi/slack-github-action@v1.24.0
+        uses: slackapi/slack-github-action@v1.26.0
         env:
           # for non-CLI-team-owned plugins, you can send this anywhere you like
           SLACK_WEBHOOK_URL: ${{ secrets.CLI_ALERTS_SLACK_WEBHOOK }}