Clear release notes

[satvu]

Issue describing the changes in this PR

Released https://github.com/Azure/azure-functions-dotnet-worker/releases/tag/http-aspnetcore-extension-1.3.1 so clearing release notes.

Pull request checklist

• My changes do not require documentation changes
  • Otherwise: Documentation issue linked to PR
• My changes should not be added to the release notes for the next release
  • Otherwise: I've added my notes to release_notes.md
• My changes do not need to be backported to a previous version
  • Otherwise: Backport tracked by issue/PR #issue_or_pr
• I have added all required tests (Unit tests, E2E tests)

Additional information

Additional PR information

[0xced]

Note that if #2486 is merged then this pull request can be closed without merging since #2486 adds new release notes for Microsoft.Azure.Functions.Worker.Extensions.Http.AspNetCore.