Update Dockerfile and global.json updates

Author: renovate[bot]

.devcontainer/Dockerfile

@@ -1,5 +1,5 @@
 # Refer to https://hub.docker.com/_/microsoft-dotnet-sdk for available versions
-FROM mcr.microsoft.com/dotnet/sdk:9.0.200-noble
+FROM mcr.microsoft.com/dotnet/sdk:9.0.300-noble@sha256:58fa5442c6da3bd654cab866fd6668de2713769511e412a3aa23c14368b84b16
 
 # Installing mono makes `dotnet test` work without errors even for net472.
 # But installing it takes a long time, so it's excluded by default.

global.json

@@ -1,6 +1,6 @@
 {
   "sdk": {
-    "version": "9.0.200",
+    "version": "9.0.203",
     "rollForward": "patch",
     "allowPrerelease": false
   },