Replace unmaintained lodash per-method packages with full lodash

[gorner]

CVE-2021-23337 was recently updated to reflect an issue previously patched in Lodash also being present in the lodash.template package, which from all appearances is no longer maintained, resulting in users receiving NPM/GitHub alerts related to this advisory. For that matter, lodash.foreach appears to be similarly unmaintained.

I should emphasize there's nothing I've seen to suggest that sourcemap-validator's usage is risky but in my mind it is still something worth fixing.

Under the circumstances I've replaced these two sub-packages with the current full version of lodash, and adjusted require calls where needed.

I would also request to back-merge this update to the v1 release line if possible.

[legobeat]

Maintainer last GitHub activity is 2020. If anyone is inclined to take on publishing a fork with this fix, that would be a good thing.