Feature request: Support major.minor in global.json for aspnetcore

- [ ] This issue is blocking
- [x] This issue is causing unreasonable pain

There is currently no mechanism such as darc/maestro to automatically keep up to date the version of aspnetcore that is referenced in a global.json. The dotnet/wcf repo has a global.json file that looks similar to the following:
```json
{
"tools": {
"dotnet": "10.0.100",
"runtimes": {
"aspnetcore": [
"8.0.22",
"10.0.1"
]
}
},
"sdk": {
"version": "10.0.100"
},
"msbuild-sdks": {
"Microsoft.DotNet.Arcade.Sdk": "11.0.0-beta.25615.1",
"Microsoft.DotNet.Helix.Sdk": "11.0.0-beta.25615.1"
}
}
```
It's a manual process to keep updating the aspnetcore version as new releases come out, and as a result often gets missed, sometimes for long durations of time. It would be sufficient for WCF's needs to simply support specifying major.minor for the versions and automatically using the latest version that's available.