[DDW-778] Update README with Nix SSL issue solution steps

Author: tomislavhoracek

README.md

@@ -35,6 +35,15 @@ Daedalus - Cryptocurrency Wallet
    ```
 3. Run `nix-shell` with correct list of arguments or by using existing `package.json` scripts to load a shell with all the correct versions of all the required dependencies for development.
 
+**Notes:**
+If you get SSL error when running `nix-shell` (SSL peer certificate or SSH remote key was not OK) try the next steps:
+1. Reinstall nix
+  ```bash
+  $ nix-env -e *
+  $ curl -L https://nixos.org/nix/install | sh
+  ```
+2. Download certificate from https://docs.certifytheweb.com/docs/kb/kb-202109-letsencrypt/ and import to your keychain.
+
 ## Development
 
 ### Running Daedalus with Cardano Node