chore: fix ignore paths in .codecov.yml (pingcap#50175)

close pingcap#50174

Author: wuhuizuo

.codecov.yml

@@ -72,24 +72,24 @@ flag_management:
 
 ignore:
   - "LICENSES"
-  - "*_test.go"
+  - "**/*_test.go"
   - ".git"
-  - "*.yml"
-  - "*.md"
-  - "cmd/.*"
-  - "docs/.*"
-  - "vendor/.*"
-  - "pkg/ddl/failtest/.*"
-  - "pkg/ddl/testutil/.*"
-  - "pkg/executor/seqtest/.*"
-  - "pkg/metrics/.*"
-  - "pkg/expression/generator/.*"
-  - "br/pkg/mock/.*"
-  - "pkg/testkit/**/*"
-  - "pkg/server/internal/testutil/**/*"
-  - "pkg/statistics/handle/cache/internal/testutil/.*"
+  - "**/*.yml"
+  - "**/*.md"
+  - "cmd"
+  - "docs"
+  - "vendor"
+  - "pkg/ddl/failtest"
+  - "pkg/ddl/testutil"
+  - "pkg/executor/seqtest"
+  - "pkg/metrics"
+  - "pkg/expression/generator"
+  - "br/pkg/mock"
+  - "pkg/testkit"
+  - "pkg/server/internal/testutil"
+  - "pkg/statistics/handle/cache/internal/testutil"
   - "pkg/session/testutil.go"
   - "pkg/store/mockstore/unistore/testutil.go"
-  - "k8s.io/apimachinery/pkg/**/*"
-  - "build/**/*"
+  - "k8s.io/apimachinery/pkg"
+  - "build"