[rayci] build release binaries for all supported platforms (#219)

`rayci` only supports linux amd64, `wanda` supports linux amd64, arm64
and windows amd64.

.buildkite/release.rayci.yaml

@@ -1,7 +1,11 @@
 group: release
 steps:
-  - name: hello-release
+  # Use release queue to build rayci and wanda release binaries.
+  # This makes sure that the release queue is working and also
+  # builds the releases and save the binaries in build artifacts.
+  - name: rayci and wanda binaries
     instance_type: release
     commands:
-      - echo "Hello, Release!"
+      - bash release.sh
+      - cp _release/* /artifact-mount
     depends_on: forge

release.sh

@@ -5,8 +5,22 @@ set -euxo pipefail
 mkdir -p _release
 rm -f _release/*
 
-RAYCI_OS="$(go env GOOS)"
-RAYCI_ARCH="$(go env GOARCH)"
+function build_rayci {
+	RAYCI_OS="$1"
+	RAYCI_ARCH="$2"
 
-go build -trimpath -o "_release/rayci-${RAYCI_OS}-${RAYCI_ARCH}" .
-go build -trimpath -o "_release/wanda-${RAYCI_OS}-${RAYCI_ARCH}" ./wanda/wanda
+	GOOS="$RAYCI_OS" GOARCH="$RAYCI_ARCH" go build -trimpath -o "_release/rayci-${RAYCI_OS}-${RAYCI_ARCH}" .
+}
+
+function build_wanda {
+	RAYCI_OS="$1"
+	RAYCI_ARCH="$2"
+
+	GOOS="$RAYCI_OS" GOARCH="$RAYCI_ARCH" go build -trimpath -o "_release/wanda-${RAYCI_OS}-${RAYCI_ARCH}" ./wanda/wanda
+}
+
+build_rayci linux amd64
+
+build_wanda linux amd64
+build_wanda linux arm64
+build_wanda windows amd64