Use non-deprecated macOS pool on Azure Pipelines (#1847)
Use non-deprecated macOS pool on Azure Pipelines (#1847)

Fixes the warning: "The macOS-10.14 environment is deprecated and will be removed on December 10, 2021. For more details see https://devblogs.microsoft.com/devops/hosted-pipelines-image-deprecation/"
adamsitnik/BenchmarkDotNet,Ky7m/BenchmarkDotNet,PerfDotNet/BenchmarkDotNet,Ky7m/BenchmarkDotNet,Ky7m/BenchmarkDotNet,adamsitnik/BenchmarkDotNet,adamsitnik/BenchmarkDotNet,PerfDotNet/BenchmarkDotNet,Ky7m/BenchmarkDotNet,PerfDotNet/BenchmarkDotNet,adamsitnik/BenchmarkDotNet