Add known host for ssh binary cache push

.gitea/workflows/test.yaml

@@ -46,13 +46,16 @@ jobs:
           cat ./.test_file
           base64 ./.test_file
 
-      - name: Setup SSH Key
+      - name: Setup SSH For Pushing to Binary Cache
         run: |
+          # Set up push key with ssh-agent
           echo "${{ secrets.BINARY_CACHE_PUSH_SSH_KEY }}" | base64 -d > ./.id_ed25519
           chmod 600 ./.id_ed25519
           eval $(ssh-agent -a $SSH_AUTH_SOCK)
-          md5sum ./.id_ed25519
           ssh-add ./.id_ed25519
+          # Add Binary Cache as known host
+          mkdir -p ~/.ssh
+          echo "s0.koi-bebop.ts.net ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIAwiXcUFtAvZCayhu4+AIcF+Ktrdgv9ee/mXSIhJbp4q" | tee -a ~/.ssh/known_hosts
 
       - name: Copy all built derivations to remote cache
         run: nix copy --to ssh://cache-push@s0.koi-bebop.ts.net /nix/store/*