Added new pun to puns.json

[virejdasani]

Added this to puns.json:

  {
    "pun": "Q: What did C++ say to C?",
    "punchline": "A: You have no class!"
  }

[github-actions[bot]]

Thank you for submitting a PR! Here's a pun, while you wait for me to review it.

Q: Why do app developer's have such high insurance rates? A: They're always crashing!

Or you can ping me on Twitter, that tends to speed up this process!

[AlexLakatos]

Thanks for the PR & Happy Hacktoberfest!