Update the tutorial for creating a project (#89)

docs/tutorials/create-a-project.mdx

@@ -47,25 +47,23 @@ The `soroban-sdk` is in early development. Report issues
 soroban-sdk = "0.0.4"
 
 [dev_dependencies]
-project-name = { path = ".", features = ["testutils"] }
+soroban-sdk = { version = "0.0.4", features = ["testutils"] }
 
 [features]
-default = ["export"]
-export = []
 testutils = ["soroban-sdk/testutils"]
 ```
 
-The `features` list and `dev_dependencies` configure three variations that the
-contract can be built with:
-- By `default`, with `export` enabled, contract functions will be exported and
-available to be invoked when the contract is deployed.
-- Optionally without `export` enabled, contract functions will not be exported.
-Types will be still exposed, which is useful when developing multiple contracts
-together and this contract is to be imported into another but its functions are
-not intended to be invoked.
-- And `testutils` which will cause additional test utilities to be generated for
-calling the contract in tests. The library itself is added as a `dev_dependencies`
-so that whenever its tests are running the `testutils` feature is enabled.
+The `features` list includes a `testutils` feature, which will cause additional
+test utilities to be generated for calling the contract in tests.
+
+:::info
+The `testutils` test utilities are automatically enabled inside [Rust unit
+tests] inside the same crate as your contract. If you write [Rust integration
+tests], or write tests from another crate, you'll need to add `#[cfg(feature =
+"testutils")]` to those tests and enable the `testutils` feature when running
+your tests with `cargo test --features testutils` to be able to use those test
+utilities.
+:::
 
 ## Configure the `release` Profile
 
@@ -92,24 +90,17 @@ lto = true
 The steps below should produce a `Cargo.toml` that looks like so.
 
 ```toml title="Cargo.toml"
-[package]
-name = "project-name"
-version = "0.1.0"
-edition = "2021"
-
 [lib]
 crate-type = ["cdylib", "rlib"]
 
+[features]
+testutils = ["soroban-sdk/testutils"]
+
 [dependencies]
 soroban-sdk = "0.0.4"
 
 [dev_dependencies]
-project-name = { path = ".", features = ["testutils"] }
-
-[features]
-default = ["export"]
-export = []
-testutils = ["soroban-sdk/testutils"]
+soroban-sdk = { version = "0.0.4", features = ["testutils"] }
 
 [profile.release]
 opt-level = "z"
@@ -121,3 +112,6 @@ panic = "abort"
 codegen-units = 1
 lto = true
 ```
+
+[Rust unit tests]: https://doc.rust-lang.org/rust-by-example/testing/unit_testing.html
+[Rust integration tests]: https://doc.rust-lang.org/rust-by-example/testing/integration_testing.html