Enable FxCop Analyzers

[heaths]

Building on #7467, we should enable FxCop analyers: https://docs.microsoft.com/visualstudio/code-quality/install-fxcop-analyzers. Not only is this recommended by TwC but it allows us to catch things like catch (Exception ex) { /* do stuff */ throw ex; } (CA2200).

To note, some of this can be enabled via our existing .editorconfig: https://docs.microsoft.com/dotnet/fundamentals/code-analysis/code-quality-rule-options

[heaths]

We might start with .NET's https://github.com/dotnet/runtime/blob/master/eng/CodeAnalysis.ruleset since we started with their .editorconfig as well (with 1 small tweak I don't remember).

[pakrym]

Update the package to the latest version.