Remove reference to unmaintained repository (#427)

* Remove reference to unmaintained repository

* Update README.md

Author: calavera

README.md

@@ -176,7 +176,7 @@ $ npx serverless invoke -f hello -d '{"foo":"bar"}'
 
 #### Docker
 
-Alternatively, you can build a Rust-based Lambda function in a [docker mirror of the AWS Lambda provided runtime with the Rust toolchain preinstalled](https://github.com/softprops/lambda-rust).
+Alternatively, you can build a Rust-based Lambda function in a [docker mirror of the AWS Lambda provided runtime with the Rust toolchain preinstalled](https://github.com/rustserverless/lambda-rust).
 
 Running the following command will start a ephemeral docker container which will build your Rust application and produce a zip file containing its binary auto-renamed to `bootstrap` to meet the AWS Lambda's expectations for binaries under `target/lambda_runtime/release/{your-binary-name}.zip`, typically this is just the name of your crate if you are using the cargo default binary (i.e. `main.rs`)
 
@@ -186,7 +186,7 @@ $ docker run --rm \
     -v ${PWD}:/code \
     -v ${HOME}/.cargo/registry:/root/.cargo/registry \
     -v ${HOME}/.cargo/git:/root/.cargo/git \
-    softprops/lambda-rust
+    rustserverless/lambda-rust
 ```
 
 With your application build and packaged, it's ready to ship to production. You can also invoke it locally to verify is behavior using the [lambdaci :provided docker container](https://hub.docker.com/r/lambci/lambda/) which is also a mirror of the AWS Lambda provided runtime with build dependencies omitted.