docs: Highlight piping to bash goes against conventional wisdom

This commit updates nilup-install docs to include a note about piping to
bash going against conventional security wisdom and to show our users
support in inspecting what the install.sh script does before running it
blindly from their machine.

README.md

@@ -7,6 +7,10 @@ This template has all the power of the [Scaffold-ETH 2 dapp toolkit](https://git
 Before you begin, you need to install the following tools:
 
 - `nilup`, an installer and version manager for the [Nillion SDK tools](https://docs.nillion.com/nillion-sdk-and-tools). Install nilup:
+
+  _For the security-conscious, please download the `install.sh` script, so that you can inspect how
+  it works, before piping it to `bash`._
+
   ```
   curl https://nilup.nilogy.xyz/install.sh | bash
   ```