Use language server and infer gopath

.devcontainer/devcontainer.json

@@ -11,6 +11,8 @@
 		"seccomp=unconfined"
 	],
 	"settings": {
-		"go.gopath": "/go"
+		"go.gopath": "/go",
+		"go.inferGopath": true,
+		"go.useLanguageServer": true
 	}
 }

.vscode/settings.json

@@ -0,0 +1,4 @@
+{
+    "go.useLanguageServer": true,
+    "go.inferGopath": true
+}