新增learn-kubernetes（https://github.com/yyong-brs/learn-kubernetes）相关文件

learn/learn-kubernetes-master/kiamol/ch11/lab/bulletin-board/ci/build.sh

@@ -0,0 +1,8 @@
+#!/bin/sh
+
+buildctl --addr tcp://buildkitd:1234 \
+  build \
+  --frontend=gateway.v0 \
+  --opt source=kiamol/buildkit-buildpacks \
+  --local context=src \
+  --output type=image,name=${REGISTRY_SERVER}/${REGISTRY_USER}/bulletin-board:${BUILD_NUMBER}-kiamol,push=true