Update apache/skywalking-eyes digest to c4b6b31

Author: renovate[bot]

.github/workflows/license-check.yaml

@@ -6,4 +6,4 @@ jobs:
     steps:
     - uses: actions/checkout@master
     - name: Check License Header
-      uses: apache/skywalking-eyes/header@477772b7ef382b9024ac89676ebe6cbb26165a4f
+      uses: apache/skywalking-eyes/header@c4b6b3195c028447a395aeec8053cae2d6cfd0b5