Incorrect plugin adding by wheel path

• I am on the latest Poetry version.
• I have searched the issues of this repo and believe that this is not a duplicate.
• If an exception occurs when executing a command, I executed it again in debug mode (-vvv option).

• OS version and name: Darwin Kernel Version 20.2.0
• Poetry version: 1.2.0
• Link of a Gist with the contents of your pyproject.toml file: https://github.com/topenkoff/poetry-release/blob/poetry_update/pyproject.toml

Issue

I have created a plugin, and after stable poetry release, i update plugin dependency version in pyproject.toml. After, i build wheel via poetry build and try to install this wheel with flag --allow-prereleases. Plugin was installed correct and works, but i can't see list of installed plugins

poetry-release on  poetry_update [$] is 📦 v0.3.1-alpha.0 via 🐍 v3.7.2
❯ poetry build
Building poetry-release (0.3.1-alpha.0)
  - Building sdist
  - Built poetry-release-0.3.1a0.tar.gz
  - Building wheel
  - Built poetry_release-0.3.1a0-py3-none-any.whl

poetry-release on  poetry_update [$] is 📦 v0.3.1-alpha.0 via 🐍 v3.7.2
❯ poetry self add --allow-prereleases $(pwd)/dist/poetry_release-0.3.1a0-py3-none-any.whl

Updating dependencies
Resolving dependencies... (3.1s)

Writing lock file

Package operations: 1 install, 0 updates, 0 removals

  • Installing poetry-release (0.3.1a0 /Users/d.kayshev/sources/github/poetry-release/dist/poetry_release-0.3.1a0-py3-none-any.whl)

poetry-release on  poetry_update [$] is 📦 v0.3.1-alpha.0 via 🐍 v3.7.2 took 6s
❯ poetry self show plugins

The Poetry configuration is invalid:
  - [group.additional.dependencies.poetry-release] {'path': '/Users/d.kayshev/sources/github/poetry-release/dist/poetry_release-0.3.1a0-py3-none-any.whl', 'allow-prereleases': True} is not valid under any of the given schemas

Reproduce the issue from the reported pyproject.toml and wheel path by running poetry self add --allow-prereleases followed by poetry self show plugins. Trace the plugin dependency handling and configuration validation involved in these commands. Done means a wheel-installed plugin can be listed without the reported invalid-configuration error.