Accommodate 17.x branch names (#5174) (#5175)

hooks/post_push

@@ -0,0 +1,14 @@
+#!/bin/bash
+
+set -e
+
+# If this is an archive branch (like v1.4 or v1.11),
+# build and push the docs-base branch at the end of
+# a successful build of the branch
+
+if [[ $SOURCE_BRANCH =~ (^v1\.[0-9]+$|^v1[7-9]\.[0-9]+$) ]]; then
+  git fetch origin docs-base:docs-base --depth 1 || ( echo "Couldn't fetch docs-base." && exit 1 )
+  git checkout docs-base || ( echo "Couldn't check out docs-base." && exit 1 )
+  docker build -t docs/docker.github.io:docs-base . || ( echo "Couldn't build docs-base Dockerfile." && exit 1 )
+  docker push docs/docker.github.io:docs-base || ( echo "Coudn't push new docs-base image." && exit 1 )
+fi