Move GitHub actions over to pnpm to speed up CI/CD

[boyney123]

Use Case

The generators and SDK use PNPM and things are rapid, I'm wondering if that would be the same case if we did that for the main repo? Something to explore!

Proposed Solution

No response

Implementation Notes

No response

Community Notes

• Please vote by adding a 👍 reaction to the issue to help us prioritize.
• If you are interested to work on this issue, please leave a comment.
• If this issue is labeled needs-discussion, it means the spec has not been finalized yet. Please reach out in the EventCatalog Discord.

[carlosallexandre]

We could do that.

But somethings should be addressed first - #680 and #831.

And finally, #575.