Update release to match .net 8 version

.github/workflows/release.yml

@@ -18,7 +18,7 @@ jobs:
         submodules: true
     - uses: actions/setup-dotnet@v4
       with:
-        dotnet-version: '6.0.*'
+        dotnet-version: '8.0.*'
     - run: dotnet publish -c Release .\OhmGraphite\
     - name: Set artifact name
       shell: bash