Handle no existing changelog (#82)

Author: Qalthos

collection_prep/cmd/version.py

@@ -40,6 +40,9 @@
 
 def get_last_version(path) -> str:
     changelog_path = path / "changelogs" / "changelog.yaml"
+    if not changelog_path.exists:
+        # Collection has not been released?
+        return "0.0.0"
     changelog = yaml.load(changelog_path)
     return max(changelog["releases"].keys())