docs : alpine package

Signed-off-by: Guillaume de Rouville <guillaume.derouville@gmail.com>

stdlib/alpine/alpine.cue

@@ -5,13 +5,17 @@ import (
 	"dagger.io/dagger/op"
 )
 
+// Default Alpine version
 let defaultVersion = "3.13.5@sha256:69e70a79f2d41ab5d637de98c1e0b055206ba40a8145e7bddb55ccc04e13cf8f"
 
 // Base image for Alpine Linux
 #Image: {
+	// List of packages to install
 	package: [string]: true | false | string
+	// Alpine version to install
 	version: string | *defaultVersion
 
+	// Use of os package not possible : alpine is a low level component
 	#up: [
 		op.#FetchContainer & {
 			ref: "index.docker.io/alpine:\(version)"