[Chore] Bump LTS to 18.10

Description

This MR bumps the LTS version from 17.9 to 18.10.

LIGO will need to be integrated with Morley Debugger soon, and to avoid downgrading LIGO LSP's LTS version, we preferred to instead bump everything up.

Related issue(s)

Resolves None

Pre-condition to resolve LIGO-288

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