update dev dependencies including typescript, gts

[hyangah]

That will clear npm audit too (context: golang/go#71118)

Upgrade

• gts to 6.0.2
• typescript >=5

[gopherbot]

Change https://go.dev/cl/640536 mentions this issue: extension/package.json: update typescript, gts versions

[findleyr]

CC @h9jiang