Markdown URL errors in docs

[mthalman]

The following errors are showing up for the check-markdown-links workflow in this repo:

 Running linkspector with reviewdog 🐶 ...
  message:"Cannot reach https://dotnet.microsoft.com/en-us/platform/support/policy/dotnet-core Status: null net::ERR_NAME_NOT_RESOLVED at https://dotnet.microsoft.com/en-us/platform/support/policy/dotnet-core"  location:{path:"README.md"  range:{start:{line:127  column:3}  end:{line:128  column:84}}}  severity:ERROR  source:{name:"linkspector"  url:"https://github.com/UmbrellaDocs/linkspector"}
  message:"Cannot reach https://dotnet.microsoft.com/en-us/download/dotnet Status: null net::ERR_NAME_NOT_RESOLVED at https://dotnet.microsoft.com/en-us/download/dotnet"  location:{path:"Documentation/bootstrapping-guidelines.md"  range:{start:{line:90  column:38}  end:{line:91  column:62}}}  severity:ERROR  source:{name:"linkspector"  url:"https://github.com/UmbrellaDocs/linkspector"}
  reviewdog: found at least one issue with severity greater than or equal to the given level: any
  Error: [Linkspector] reported by reviewdog 🐶
  Cannot reach https://dotnet.microsoft.com/en-us/platform/support/policy/dotnet-core Status: null net::ERR_NAME_NOT_RESOLVED at https://dotnet.microsoft.com/en-us/platform/support/policy/dotnet-core
  
  Raw Output:
  message:"Cannot reach https://dotnet.microsoft.com/en-us/platform/support/policy/dotnet-core Status: null net::ERR_NAME_NOT_RESOLVED at https://dotnet.microsoft.com/en-us/platform/support/policy/dotnet-core"  location:{path:"README.md"  range:{start:{line:127  column:3}  end:{line:128  column:84}}}  severity:ERROR  source:{name:"linkspector"  url:"https://github.com/UmbrellaDocs/linkspector"}
  Error: [Linkspector] reported by reviewdog 🐶
  Cannot reach https://dotnet.microsoft.com/en-us/download/dotnet Status: null net::ERR_NAME_NOT_RESOLVED at https://dotnet.microsoft.com/en-us/download/dotnet
  
  Raw Output:
  message:"Cannot reach https://dotnet.microsoft.com/en-us/download/dotnet Status: null net::ERR_NAME_NOT_RESOLVED at https://dotnet.microsoft.com/en-us/download/dotnet"  location:{path:"Documentation/bootstrapping-guidelines.md"  range:{start:{line:90  column:38}  end:{line:91  column:62}}}  severity:ERROR  source:{name:"linkspector"  url:"https://github.com/UmbrellaDocs/linkspector"}