adding metal sepolia

Author: sbvegan

pages/builders/notices/holocene-changes.mdx

@@ -66,7 +66,7 @@ These following steps are necessary for every node operator:
   <Callout type="warning">
     If you are operating a node for an OP Chain that have opted into the [hardfork activation inheritance behavior](https://github.com/ethereum-optimism/superchain-registry/blob/main/docs/hardfork-activation-inheritance.md), the Holocene activation date is part of the `op-node` and `op-geth` nodes. So, no action is needed for the sequencer after upgrading to the latest release. Please skip to [Step 3: Verify Your Configuration](#verify-your-configuration).
 
-    For Sepolia that is: `OP Sepolia`, `Base Sepolia`, `Mode Sepolia`, and `Zora Sepolia`.
+    For Sepolia that is: `OP Sepolia`, `Base Sepolia`, `Mode Sepolia`, `Zora Sepolia`, and `Metal Sepolia`.
   </Callout>
 
   For node operators of not included in the [hardfork activation inheritance behavior](https://github.com/ethereum-optimism/superchain-registry/blob/main/docs/hardfork-activation-inheritance.md), you will need to manually configure the activation. This can be done one of two ways: