dotnet: amend dev-cert script in README (#1103)

src/dotnet/README.md

@@ -64,8 +64,10 @@ The contents of `.devcontainer/setup-dotnet-dev-cert.sh`:
 # Change ownership of the .dotnet directory to the vscode user (to avoid permission errors)
 sudo chown -R vscode:vscode /home/vscode/.dotnet
 
-# Export the ASP.NET Core HTTPS development certificate to a PEM file
 # If there is no development certificate, this command will generate a new one
+dotnet dev-certs https
+
+# Export the ASP.NET Core HTTPS development certificate to a PEM file
 sudo -E dotnet dev-certs https --export-path /usr/local/share/ca-certificates/dotnet-dev-cert.crt --format pem
 
 # Add the PEM file to the trust store