Add some default extenstions to devconainer (#1)

Author: SRv6d

.devcontainer/devcontainer.json

@@ -1,4 +1,17 @@
 {
   "name": "Rust",
-  "image": "mcr.microsoft.com/devcontainers/rust"
+  "image": "mcr.microsoft.com/devcontainers/rust",
+  "customizations": {
+    "vscode": {
+      "extensions": [
+        "rust-lang.rust-analyzer",
+        "serayuzgur.crates",
+        "tamasfe.even-better-toml",
+        "Swellaby.vscode-rust-test-adapter"
+      ],
+      "settings": {
+        "rust-analyzer.updates.askBeforeDownload": false
+      }
+    }
+  }
 }