Further fix for #254

I hadn't followed all of the instructions on
  https://learn.microsoft.com/en-gb/nuget/nuget-org/trusted-publishing

Author: craigfowler

.github/workflows/releaseBuild.yml

@@ -89,6 +89,7 @@ jobs:
     needs: build_and_pack
     permissions:
       actions: read
+      id-token: write
     steps:
       - name: Add .NET global tools location to PATH
         run: echo "$HOME/.dotnet/tools" >> "$GITHUB_PATH"
@@ -102,7 +103,12 @@ jobs:
         with:
           name: Build results (NuGet)
           path: ./packages
+      - name: Log into NuGet & get short-lived API key
+        uses: NuGet/login@v1
+        id: nuget-login
+        with:
+          user: ${{ secrets.NUGET_USER }}
       - name: Publish to NuGet
-        run: dotnet nuget push ./packages/*.nupkg --source https://api.nuget.org/v3/index.json
+        run: dotnet nuget push ./packages/*.nupkg --source https://api.nuget.org/v3/index.json --api-key ${{ steps.nuget-login.outputs.NUGET_API_KEY }}