ci: skip scp2p-core publish if already on crates.io

Author: techartdev

.github/workflows/release-core.yml

@@ -207,6 +207,7 @@ jobs:
 
       - name: Publish scp2p-core
         if: ${{ env.CARGO_REGISTRY_TOKEN != '' }}
+        continue-on-error: true   # skip gracefully if already published
         run: |
           cargo publish --package scp2p-core --no-verify
           sleep 20