Fix description about --configuration

[slado]

According to the documentation, the configuration supports only Debug and Release
-c|--configuration {Debug|Release}

But actually it supports any configuration, even user defined.

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Document Details

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• ID: 211afdc7-c796-202d-239d-823f2a499dff
• Version Independent ID: 9439897e-dcb3-bc2e-5cae-35c1ca2e0681
• Content: dotnet publish command - .NET Core CLI
• Content Source: docs/core/tools/dotnet-publish.md
• Product: dotnet-core
• Technology: dotnet-cli
• GitHub Login: @mairaw
• Microsoft Alias: mairaw

[Thraka]

Hello! Thank you for filing this issue. We're in the middle of updating a lot of the CLI docs.

@mairaw I figured you could fix this during your other updates to the CLI docs. Assigning to you but leaving the project/milestone settings up to you.