fix(v2): inability for users to pin their docusaurus version

[BuckyMaler]

Motivation

These changes allow users to pin their version of Docusaurus. If a users package.json had the following:

"dependencies": {
  "@docusaurus/core": "2.0.0-alpha.59",
  "@docusaurus/preset-classic": "2.0.0-alpha.59",
  ...
}

They'd expect the version of all @docusaurus packages to be 2.0.0-alpha.59, but that's not the case because for example packages/docusaurus/package.json has "@docusaurus/types": "^2.0.0-alpha.59" and because of the caret version range 2.0.0-alpha.60 of @docusaurus/types is installed.

Have you read the Contributing Guidelines on pull requests?

Yes

Closes #3161

[docusaurus-bot]

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[slorber]

I see, so the problem is transitive dependencies might use a newer incompatible version, makes sense thanks

[slorber]

Unfortunately this feature keeps being removed, as Lerna publish does add the ^ back :(

[BuckyMaler]

Lerna has an exact option for its version command and it seems it could be useful for publish if used in lerna.json.

lerna/lerna#2397 (comment)

[slorber]

Thanks,

Related to:
#3386
#3371