fix(Plugin): don't install plugins globally

[seven1m]

This fixes a problem where @prettier/plugin-ruby was not being used.

Config:

  prettier:
    runs-on: ubuntu-latest

    steps:
      - uses: actions/checkout@v2
        with:
          ref: ${{ github.head_ref }}
      - uses: creyD/[email protected]
        with:
          prettier_plugins: "@prettier/plugin-ruby"
          prettier_options: "--write ."

Before:

After:

[seven1m]

@creyD any interest in this?

[creyD]

@seven1m Yes, sorry for the late reply. Will merge this to dev for now. Will be included in the next version.

[seven1m]

Thank you!