ci: add codecov file

.codecov.yml

@@ -0,0 +1,48 @@
+codecov:
+  require_ci_to_pass: true
+
+coverage:
+  precision: 2
+  round: down
+  range: "70...100"
+
+  status:
+    project:
+      default:
+        target: auto
+        threshold: 1%
+        base: auto
+        branches:
+          - main
+        if_ci_failed: error
+        informational: false
+        only_pulls: false
+
+    patch:
+      default:
+        target: auto
+        threshold: 1%
+        base: auto
+        if_ci_failed: error
+        only_pulls: true
+
+    changes: false
+
+comment:
+  layout: "diff, flags, files"
+  behavior: default
+  require_changes: false
+  require_base: false
+  require_head: true
+  hide_project_coverage: false
+
+parsers:
+  gcov:
+    branch_detection:
+      conditional: true
+      loop: true
+      macro: false
+      method: false
+
+github_checks:
+  annotations: true