CI: Create a job that checks for outdated libraries

Updating libraries is always a manual job.

We have three sets of solutions:

- The main library
- The template
- The samples

Create a github actions workflow called `check-outdated`:

- Runs [dotnet-outdated](https://github.com/dotnet-outdated/dotnet-outdated) on each solution.
- Reports (in the CI summary) the libraries to be updated.
- For each outdated library:
- Determine if there is an issue titled "Update " that is open. Create one per the below spec if not. If it does exist, see if it needs updating
- Change issue title to "Update to X.Y.Z" (where X.Y.Z is the new library version)
- Record in the body of the issue the list of solutions/projects needing updating

This is likely to be a script - node/JavaScript scripts are fine, stored in `scripts`