ci: Enforce coverage (#238)

Signed-off-by: oliver könig <okoenig@nvidia.com>

Author: ko3n1g

codecov.yml

@@ -1,7 +1,20 @@
 comment: false
 coverage:
   status:
-    patch: false
-    project: false
+    patch:
+      default:
+        target: 80%
+        threshold: 0%
+        base: auto
+        if_ci_failed: error
+    project:
+      default:
+        target: 80%
+        threshold: 0%
+        base: auto
+        if_ci_failed: success
+        only_pulls: false
+        branches:
+          - main
 fixes:
   - "/opt/NeMo-Run/::"