ci: add script to open pr to update bazel builder version

build/teamcity/internal/cockroach/build/ci/open-new-bazel-builder-image-pr.sh

@@ -0,0 +1,44 @@
+#!/usr/bin/env bash
+set -xeuo pipefail
+
+# This script expects the following env vars to be set:
+#   BRANCH [branch name to be created in fork]
+#   VERSION [new version to echo into build/.bazelbuilderversion]
+#   GH_TOKEN [github token]
+
+dir="$(dirname $(dirname $(dirname $(dirname $(dirname $(dirname "${0}"))))))"
+source "$dir/teamcity-common-support.sh"
+
+git_ssh() {
+  # $@ passes all arguments to this function to the command
+  GIT_SSH_COMMAND="ssh -i $dir/.cockroach-teamcity-key" git "$@"
+}
+
+# Install `gh` tool.
+wget -O /tmp/gh.tar.gz https://github.com/cli/cli/releases/download/v2.13.0/gh_2.13.0_linux_amd64.tar.gz
+echo "9e833e02428cd49e0af73bc7dc4cafa329fe3ecba1bfe92f0859bf5b11916401  /tmp/gh.tar.gz" | sha256sum -c -
+tar --strip-components 1 -xf /tmp/gh.tar.gz
+export PATH=$PWD/bin:$PATH
+
+# Configure git.
+git config --global user.email "[email protected]"
+git config --global user.name "cockroach-teamcity"
+configure_git_ssh_key
+trap "rm -f $dir/.cockroach-teamcity-key" EXIT
+WORKDIR="$(mktemp -d ./workdir.XXXXXX)"
+
+git_ssh clone "ssh://[email protected]/cockroachdb/cockroach.git" "$WORKDIR/cockroach" && cd "$WORKDIR/cockroach"
+
+# Push commit to fork.
+git checkout -b "$BRANCH"
+echo -n "$VERSION" > build/.bazelbuilderversion
+git commit -a -m "ci: update bazel builder image
+
+Release note: None
+Epic: None"
+git_ssh push "ssh://[email protected]/cockroach-teamcity/cockroach.git" $BRANCH
+
+# Create PR.
+gh pr create --fill --head="cockroach-teamcity:$BRANCH" --base="master"
+
+rm -rf $WORKDIR