I want to use a package that isn't published on the npm store, I have read the documentation which says that it should be like:

<protocol>://[<user>[:<password>]@]<hostname>[:<port>][:][/]<path>[#<commit-ish> | #semver:<semver>]

So, I added the line:

"@solana/spl-stake-pool": "git+https://github.com:solana-labs/solana-program-library/tree/master/stake-pool/js#^0.1.0",

which has the correct format: protocol:://<hostname>/<path>.

However, I get an error:

npm ERR! code ENOENT
npm ERR! syscall open
npm ERR! path ~/.npm/_cacache/tmp/git-clonefNeI7r/package.json
npm ERR! errno -2
npm ERR! enoent ENOENT: no such file or directory, open '~/.npm/_cacache/tmp/git-clonefNeI7r/package.json'
npm ERR! enoent This is related to npm not being able to find a file.

The url has a package.json, and if I remove this dependency, I get no error. What's the issue?