fix: correct dependabot ecosystem config (#18)

## Summary
- Remove `pip` ecosystem (no `requirements.txt`, `setup.py`, or
`pyproject.toml` exists)
- Keep `github-actions` as baseline ecosystem
- Fixes weekly `dependency_file_not_found` Dependabot failures

Author: Specter099

.github/dependabot.yml

@@ -1,23 +1,8 @@
 version: 2
 updates:
-  # Keep GitHub Actions up to date
   - package-ecosystem: "github-actions"
     directory: "/"
     schedule:
       interval: "weekly"
-    labels:
-      - "dependencies"
-      - "chore"
     commit-message:
-      prefix: "chore"
-
-  # Keep Python dependencies up to date
-  - package-ecosystem: "pip"
-    directory: "/"
-    schedule:
-      interval: "weekly"
-    labels:
-      - "dependencies"
-      - "chore"
-    commit-message:
-      prefix: "chore"
+      prefix: "chore(deps):"