Add serverless framework binary installation (#397)

serverless.hcl

@@ -0,0 +1,25 @@
+description = "The Serverless Framework – Build applications on AWS Lambda and other next-gen cloud services, that auto-scale and only charge you when they run. This lowers the total cost of running and operating your apps, enabling you to build more and manage less."
+
+test = "serverless --version"
+
+linux {
+  source = "https://github.com/serverless/serverless/releases/download/v${version}/serverless-linux-x64"
+  on unpack {
+    rename { from = "${root}/serverless-linux-x64" to = "${root}/serverless" }
+  }
+}
+
+darwin {
+  source = "https://github.com/serverless/serverless/releases/download/v${version}/serverless-macos-x64"
+  on unpack {
+    rename { from = "${root}/serverless-macos-x64" to = "${root}/serverless" }
+  }
+}
+
+binaries = ["serverless"]
+
+version "3.35.2" {
+  auto-version {
+    github-release = "serverless/serverless"
+  }
+}