Update Codespaces settings

Author: devlights

.devcontainer/Dockerfile

@@ -1,5 +1,5 @@
 # [Choice] Go version: 1, 1.16, 1.17
-ARG VARIANT="1.18"
+ARG VARIANT="1.20"
 FROM mcr.microsoft.com/vscode/devcontainers/go:0-${VARIANT}
 
 # [Choice] Node.js version: none, lts/*, 16, 14, 12, 10

.devcontainer/devcontainer.json

@@ -3,7 +3,7 @@
 	"build": {
 		"dockerfile": "Dockerfile",
 		"args": {
-			"VARIANT": "1.19",
+			"VARIANT": "1.20",
 			"NODE_VERSION": "lts/*"
 		}
 	},
@@ -12,20 +12,24 @@
 		"--security-opt", 
 		"seccomp=unconfined" 
 	],
-	"settings": {
-		"go.toolsManagement.checkForUpdates": "local",
-		"go.useLanguageServer": true,
-		"go.gopath": "/go",
-		"go.goroot": "/usr/local/go"
+	"customizations": {
+		"vscode": {
+			"settings": {
+				"go.toolsManagement.checkForUpdates": "local",
+				"go.useLanguageServer": true,
+				"go.gopath": "/go",
+				"go.goroot": "/usr/local/go"
+			},
+			"extensions": [
+				"golang.Go",
+				"dracula-theme.theme-dracula"
+			]
+		}
 	},
 	"features": {
 		// https://github.com/microsoft/vscode-dev-containers/tree/main/containers/docker-from-docker#using-bind-mounts-when-working-with-docker-inside-the-container
 		"docker-in-docker": "20.10"
 	},
-	"extensions": [
-		"golang.Go",
-		"dracula-theme.theme-dracula"
-	],
 	// "forwardPorts": [],
 	"postCreateCommand": "go version ; go install honnef.co/go/tools/cmd/staticcheck@latest; go install github.com/go-task/task/v3/cmd/task@latest",
 	"remoteUser": "vscode"