Reverting Cargo.toml change

Author: jdetter

demo/Blackholio/server-rust/Cargo.toml

@@ -5,6 +5,10 @@ edition = "2021"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
+# Put this in an empty workspace. This is required because we're nested under the SpacetimeDB root
+# dir, which has its own workspace `Cargo.toml`, and this shouldn't think it's a part of that.
+[workspace]
+
 [lib]
 crate-type = ["cdylib"]