Release v2.58.0-pre1

What's Changed

• Start 2.58 development cycle. by @jtattermusch in #2267
• Update ServiceBinderBase.AddMethod annotations to allow null handler by @JamesNK in #2270
• Add request and channel to call debugging by @JamesNK in #2271
• Support disabling load balancing with SocketsHttpHandler.Properties by @JamesNK in #2274
• Remove netstandard1.5 from some projects by @JamesNK in #2279
• Add debugger display to Status by @JamesNK in #2281
• Fix detecting inherited WinHttpHandler by @JamesNK in #2288
• Dispose socket after connection failure by @JamesNK in #2287
• Bump GrpcToolsPackageVersion to 2.58.0 by @apolcyn in #2290
• Bump version to pre1 on 2.58 branch by @apolcyn in #2291

Full Changelog: v2.57.0...v2.58.0-pre1