Update generated tsconfig to match current node version

jsii 5.3+ only supports Node 18+ (and has been for a while).

We should match the default tsconfig (`lib`, `target`, `module`) to match the recommended settings from the TypeScript project
https://github.com/microsoft/TypeScript/wiki/Node-Target-Mapping#node-18

(jsii 5.2 supports Node16, so this should not be backported or we should use the older settings)

We can only change these in new minor versions, otherwise it's breaking (particularly module).

Locate the code that generates the default tsconfig and compare its lib, target, and module settings with the TypeScript Node 18 target mapping linked in the issue. Done means new minor-version output uses the recommended Node 18 settings without changing the older jsii 5.2-compatible settings.

Written by the indexing model from the issue text.