Add contributing.md for Expecto.Template

Author: farlee2121

Expecto.Template/CONTRIBUTING.md

@@ -0,0 +1,33 @@
+# Contributing
+
+## Updating the template
+
+Updating the template is simple. 
+In short, [/content/expecto](./content/expecto/) contains the files for the end user.
+You can modify these files and it will reflect in the template output.
+
+For example, if you want to update the template framework version, you just edit the `<TargetFramework>` 
+in [/content/expecto/ExpectoTemplate.fsproj](./content/expecto/ExpectoTemplate.fsproj) just like you would with any other project.
+
+
+If you want to do more advanced edits, like add a new template, consult the [template authoring docs](https://learn.microsoft.com/en-us/dotnet/core/tutorials/cli-templates-create-template-package)
+
+
+## Packing
+
+From the Expecto.Template folder, run `dotnet pack`.
+You'll probably want to update the PackageVersion first.
+
+
+## Testing Locally
+
+`dotnet pack` and then `dotnet new install path/to/nupkg/you-just-packed`
+
+## Publishing
+
+```pwsh
+$nugetApiKey = 'your-api-key'
+rm ./bin/Release/*.nupkg
+dotnet pack -c Release -o ./bin/Release/
+ls ./bin/Release/*.nupkg |% { dotnet nuget push $_ --source https://api.nuget.org/v3/index.json --api-key $nugetApiKey}
+```