Bump System.Runtime.CompilerServices.Unsafe to 4.5.3 in TraceEvent

[suprak]

When consuming TraceEvent and other libraries from a dotnet core project, there is often times a conflict with the version of System.Runtime.CompilerServices.Unsafe.

For example,

System.Memory relies on System.Runtime.CompilerServices.Unsafe >=4.5.3

Hoping to bring TraceEvent up to the same common version.

[ghost]

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