Add a devcontainer definition

Utilizes the Dockerfile created in the previous commit.

.devcontainer/devcontainer.json

@@ -0,0 +1,24 @@
+// For format details, see https://aka.ms/devcontainer.json. For config options, see the README at:
+// https://github.com/microsoft/vscode-dev-containers/tree/v0.241.1/containers/go
+{
+	"build": {
+		"dockerfile": "../Dockerfile",
+		"target": "dev"
+	},
+	// Configure tool-specific properties.
+	"customizations": {
+		// Configure properties specific to VS Code.
+		"vscode": {
+			// Set *default* container specific settings.json values on container create.
+			"settings": {
+				"go.toolsManagement.checkForUpdates": "local",
+				"go.useLanguageServer": true,
+				"go.gopath": "/go"
+			},
+			// Add the IDs of extensions you want installed when the container is created.
+			"extensions": [
+				"golang.Go"
+			]
+		}
+	}
+}