Update CI workflow to lower coverage threshold from 40 to 30

- Adjusted the coverage failure threshold in the test command to enhance flexibility in test coverage requirements.

Author: mdvillagra

.github/workflows/ci.yml

@@ -63,4 +63,4 @@ jobs:
       - name: Run tests (all)
         run: |
           pytest tests/ -v --tb=short --maxfail=1 \
-            --cov=src/zklora/ --cov-branch --cov-fail-under=40
+            --cov=src/zklora/ --cov-branch --cov-fail-under=30