upgrade-version tool should have an option to update the C# bindings

[bfops]

Currently tools/upgrade-version only bumps the version for the Rust crates. This means that when we bump versions, we often need to remember to manually bump the C# bindings versions as well.

Note: Technically, we don't always have to bump these at the same time. It's possible that we e.g. merge ABI-breaking changes into master that force a Spacetime version bump, but the C# bindings might still be compatible with the previous version.

Definition of Done

• The upgrade-version tool has an option to upgrade the C# bindings versions, which updates *.csproj files in bindings-csharp, as well as the initial project in crates/cli/src/subcommands/project/csharp/