First dogfooder doc feedback (#105)

* Expand prereqs to include preview 7

* Use DOS-style quoting

If you don't do this, in cmd shell, the single quotes can make their way into the nuget.config.

* Explicitly mention Linux containers

Otherwise, `docker load` in publish will fail.

* Link to Microsoft docs on linux containers

Author: rainersigwald

docs/INTEGRATED-DEMO.md

@@ -5,7 +5,9 @@ You should expect it to shrink noticeably over time!
 
 ## Prerequisites
 
-* Docker should be running
+* [.NET SDK 7.0.100-preview.7](https://dotnet.microsoft.com/download/dotnet/7.0) or higher
+* Docker should be installed and running
+* On Windows, Docker must be [configured for Linux containers](https://docs.microsoft.com/virtualization/windowscontainers/quick-start/quick-start-windows-10-linux)
 * You should have an environment variable called GITHUB_USERNAME, with your github username in it
 * You should have an environment variable called GITHUB_TOKEN, with a github [personal access token](https://docs.github.com/en/authentication/keeping-your-account-and-data-secure/creating-a-personal-access-token) that has `read:packages` permissions.
 
@@ -25,7 +27,7 @@ dotnet new nugetconfig
 # GITHUB_TOKEN environment variables being present, the token should have 'read:packages'
 # permissions. (replace the \ with ` if using powershell)
 dotnet nuget add source https://nuget.pkg.github.com/rainersigwald/index.json \
-    --name rainer --username '%GITHUB_USERNAME%' --password '%GITHUB_TOKEN%' \
+    --name rainer --username "%GITHUB_USERNAME%" --password "%GITHUB_TOKEN%" \
     --store-password-in-clear-text --configfile nuget.config
 
 # add a reference to the package