Refactor platform type to string to support any kind of platform

Signed-off-by: Vasek - Tom C <tom.chauveau@epitech.eu>

stdlib/europa/dagger/engine/plan.cue

@@ -28,7 +28,7 @@ package engine
 	proxy: [endpoint=string]: _#proxyEndpoint
 
 	// Configure platform execution
-	platform?: #Platform
+	platform?: string
 
 	// Execute actions in containers
 	actions: {
@@ -142,7 +142,3 @@ _#proxyEndpoint: {
 
 // A network service address
 #Address: string & =~"^(tcp://|unix://|udp://).*"
-
-// Platform supported by buildkit daemon
-#Platform: "linux/amd64" | "linux/arm64" | "linux/arm/v7" | "linux/arm/v6" |
-	"linux/s390x" | "linux/ppc64le" | "darwin/amd64" | "windows/amd64"

tests/plan/outputs/outputs.cue

@@ -9,7 +9,7 @@ engine.#Plan & {
 		data: engine.#WriteFile & {
 			input:       scratch.output
 			path:        "/test"
-			mode:     0o600
+			permissions: 0o600
 			contents:    "foobar"
 		}
 	}