[BUG] npm-version does not git-commit nor git-tag when package in subdirectory

Current Behavior:

npm version <version> is not committing the modified package.json or package-lock.json; nor git-tagging.

We were using npm version {major|minor|patch} extensively (and successfully). It stopped working once the package was moved out of the root of the repo and into a subdirectory.

Expected Behavior:

npm version <version> should continue to create a git-commit and git-tag as indicated in the docs:

If run in a git repo, it will also create a version commit and tag. This behavior is controlled by git-tag-version (see below), and can be disabled on the command line by running npm --no-git-tag-version version. It will fail if the working directory is not clean, unless the -f or --force flag is set.

Steps To Reproduce:

1. initialize an npm package in the root of an initialized git repo
2. npm version minor successfully bumps the version, commits and tags
3. move the npm package into a subdirectory of the repo
4. npm version minor still bumps the version in package.json and package-lock.json, but git is not committed nor tagged.

Environment:

• macOS 10.15.7
• node: v14.13.1
• npm: 6.14.8
• git: git version 2.28.0

This is apparently an existing bug going as far back as npm v3: https://github.com/npm/npm/issues/18795

Start by reproducing the documented steps with an npm package moved into a repository subdirectory, then trace the npm version command's handling of the package and repository roots. Done means npm version still updates package.json and package-lock.json while creating the expected git commit and tag.