document measure-test-flakiness.sh

Signed-off-by: Chao Chen <chaochn@amazon.com>

scripts/measure-test-flakiness.sh

@@ -15,6 +15,33 @@ trap '{ rm -rf -- "${temp_dir}"; }' EXIT
 
 json_file="${temp_dir}/commit-and-check-data.json"
 
+# This GraphQL query retrieves information about the most recent commits to the default branch of the "etcd" repository owned by "etcd-io".
+# Specifically, it retrieves the commit URL and the state of the status check rollup for each of the 100 most recent commits on the default branch.
+# {
+#   repository(owner: "etcd-io", name: "etcd") {
+#     defaultBranchRef {
+#       target {
+#         ... on Commit {
+#           history(first: 100) {
+#             edges {
+#               node {
+#                 ... on Commit {
+#                   commitUrl
+#                   statusCheckRollup {
+#                     state
+#                   }
+#                 }
+#               }
+#             }
+#           }
+#         }
+#       }
+#     }
+#   }
+# }
+
+# Try this above query in https://docs.github.com/en/graphql/overview/explorer
+
 curl --fail --show-error --silent -H "Authorization: token ${GITHUB_TOKEN}" \
     -X POST \
     -d '{