Update PumpSwap examples to support breaking changes in program

[smypmsa]

Message from the official Telegram channel:

Hi all, we will be doing a breaking program upgrade on pump swap on Tuesday, 4th November, 14:00 UTC. As part of the change, we require you to mark the pool account at account index 1 in pump swap buys and sells as mutable ( as opposed to readonly ). Please make the changes as soon as possible, your integration will not break if you make it mutable before we do the program upgrade.

IDL change for reference: pump-fun/pump-public-docs@ff9cbf8