Amend node version up

[ebma]

Follow-up to https://github.com/pendulum-chain/pendulum/pull/485, fixing a minor issue.

After merging #485 I tried to run the workflow but it failed because the file name was wrong.

• [x] Fix reference to file
• [x] Remove unused files

[ebma]

I'm not sure honestly. Probably best to wait for feedback from @b-yap on this.

[b-yap]

Looks fine. Merged.