Update packages to latest versions

[KodrAus]

This PR just updates our packages to their most recent versions, resolving some vulnerabilities in transient dependencies. I've also removed the nyc dev dependency, which we didn't appear to be using and pulled in a lot of stuff.

[KodrAus]

Ok, looks like we can't update node-fetch without dropping support for Node versions below 18:

Error [ERR_REQUIRE_ESM]: require() of ES Module /home/runner/work/seq-logging/seq-logging/node_modules/node-fetch/src/index.js from /home/runner/work/seq-logging/seq-logging/index.js not supported.
Instead change the require of /home/runner/work/seq-logging/seq-logging/node_modules/node-fetch/src/index.js in /home/runner/work/seq-logging/seq-logging/index.js to a dynamic import() which is available in all CommonJS modules.