transport: make error messages more informative

Change-Id: I188e1bef8ceceb6acab800e0db92f2c80abc64e5
diff --git a/.github/workflows/docker.yml b/.github/workflows/docker.yml
index 267e3f4..ab194b9 100644
--- a/.github/workflows/docker.yml
+++ b/.github/workflows/docker.yml
@@ -2,7 +2,7 @@
 on:
   push:
     tags:
-      - 'ndn-cxx-*'
+      - 'ndn-cxx-[0-9]+*'
   schedule:
     # twice a month
     - cron: '20 4 5,20 * *'