Add note to txOverrides doc

docs/modules/ROOT/pages/api-hardhat-upgrades.adoc

@@ -25,7 +25,7 @@ The following options are common to some functions.
 ** If set to `"always"`, the implementation contract is always redeployed even if it was previously deployed with the same bytecode. This can be used with the `salt` option when deploying a proxy through OpenZeppelin Defender to ensure that the implementation contract is deployed with the same salt as the proxy.
 ** If set to `"never"`, the implementation contract is never redeployed. If the implementation contract was not previously deployed or is not found in the network file, an error will be thrown.
 ** If set to `"onchange"`, the implementation contract is redeployed only if the bytecode has changed from previous deployments.
-* `txOverrides`: (`ethers.Overrides`) An ethers.js https://docs.ethers.org/v6/api/contract/#Overrides[Overrides] object to override transaction parameters, such as `gasLimit` and `gasPrice`. Applies to all transactions sent by a function with this option, even if the function sends multiple transactions.
+* `txOverrides`: (`ethers.Overrides`) An ethers.js https://docs.ethers.org/v6/api/contract/#Overrides[Overrides] object to override transaction parameters, such as `gasLimit` and `gasPrice`. Applies to all transactions sent by a function with this option, even if the function sends multiple transactions. Not currently supported with OpenZeppelin Defender deployments.
 * `useDefenderDeploy`: (`boolean`) Deploy contracts using OpenZeppelin Defender instead of ethers.js. See xref:defender-deploy.adoc[Using with OpenZeppelin Defender]. **Note**: OpenZeppelin Defender deployments is in beta and functionality related to it is subject to change.
 * `verifySourceCode`: (`boolean`) When using OpenZeppelin Defender deployments, whether to verify source code on block explorers. Defaults to `true`.
 * `relayerId`: (`string`) When using OpenZeppelin Defender deployments, the ID of the relayer to use for the deployment. Defaults to the relayer configured for your deployment environment on Defender.