Update .NET version for tools

Author: commonsensesoftware

.devcontainer/Dockerfile

@@ -1,5 +1,5 @@
 # See here for image contents: https://github.com/microsoft/vscode-dev-containers/tree/v0.177.0/containers/dotnet/.devcontainer/base.Dockerfile
 
 # [Choice] .NET version: 7.0, 6.0, 5.0
-ARG VARIANT="6.0"
+ARG VARIANT="8.0"
 FROM mcr.microsoft.com/vscode/devcontainers/dotnet

.devcontainer/devcontainer.json

@@ -20,7 +20,7 @@
   "remoteEnv": {
     "PATH": "${containerWorkspaceFolder}/.dotnet:${containerEnv:PATH}",
     "DOTNET_MULTILEVEL_LOOKUP": "0",
-    "TARGET": "net6.0",
+    "TARGET": "net8.0",
     "DOTNET_WATCH_SUPPRESS_LAUNCH_BROWSER": "true"
   },
   // Comment out connect as root instead. More info: https://aka.ms/vscode-remote/containers/non-root.

.github/workflows/codeql-analysis.yml

@@ -31,7 +31,7 @@ jobs:
       uses: actions/setup-dotnet@v3
       id: installdotnet
       with:
-        dotnet-version: 7.0.x
+        dotnet-version: 8.0.x
 
     - name: Create temporary global.json
       run: echo '{"sdk":{"version":"${{ steps.installdotnet.outputs.dotnet-version }}"}}' > ./global.json