Use `nucypher-contracts:main` as the canonical source for contract registries.

Add test to ensure github raw path is actually correct.

nucypher/blockchain/eth/registry.py

@@ -60,7 +60,7 @@ class RegistrySource(ABC):
 
 class GithubRegistrySource(RegistrySource):
 
-    _PUBLICATION_REPO = "nucypher/nucypher"
+    _PUBLICATION_REPO = "nucypher/nucypher-contracts"
     _BASE_URL = f'https://raw.githubusercontent.com/{_PUBLICATION_REPO}'
 
     name = "GitHub Registry Source"
@@ -74,7 +74,7 @@ class GithubRegistrySource(RegistrySource):
 
     def get_publication_endpoint(self) -> str:
         """Get the GitHub endpoint for the registry publication."""
-        url = f"{self._BASE_URL}/main/nucypher/blockchain/eth/contract_registry/{self.registry_name}"
+        url = f"{self._BASE_URL}/main/deployment/artifacts/{self.registry_name}"
         return url
 
     def decode(self, response: Response, endpoint: str) -> RegistryData:

tests/unit/registry/test_registry_soures.py

@@ -4,6 +4,7 @@ import pytest
 import requests
 from requests import Response
 
+from nucypher.blockchain.eth import domains
 from nucypher.blockchain.eth.registry import (
     EmbeddedRegistrySource,
     GithubRegistrySource,
@@ -58,6 +59,13 @@ def test_github_registry_source(registry_data):
     assert data == source.data
 
 
+@pytest.mark.parametrize("domain", list(domains.SUPPORTED_DOMAINS.values()))
+def test_get_actual_github_registry_file(domain):
+    source = GithubRegistrySource(domain=domain)
+    assert str(domain.eth_chain.id) in source.data
+    assert str(domain.polygon_chain.id) in source.data
+
+
 def test_local_registry_source(registry_data, test_registry_filepath):
     source = LocalRegistrySource(
         filepath=test_registry_filepath, domain=TEMPORARY_DOMAIN