Add a script to pull in rules-template files (#75)

Various helper files/scripts for cutting releases, setting up github
workflows, etc.

update_github_workflows.sh

@@ -0,0 +1,49 @@
+#!/bin/bash
+#
+# Copyright 2024 The Bazel Authors. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# Utility to properly set up the .github/workflows directory
+
+function update_github_workflows() {
+  # Die on errors, unbound variables, and pipe errors
+  set -euo pipefail
+  local rules_template_dir=$(mktemp -d /tmp/rules-templates.XXXX)
+  local rules_android_ndk_dir=$(git rev-parse --show-toplevel)
+  local rules_android_ndk_workflows="$rules_android_ndk_dir/.github/workflows"
+  mkdir -p "$rules_android_ndk_workflows"
+  git clone https://github.com/bazel-contrib/rules-template "$rules_template_dir"
+  cd "$rules_template_dir/.github/workflows"
+  local rules_template_commit=$(git rev-parse HEAD)
+
+  # For every file in rules-template/.github/workflows, substitute the placeholder
+  # 'rules_mylang' for rules_android_ndk and write out the resulting file back to
+  # rules_android_ndk/.github/workflows.
+  for ci_file in $(ls); do
+    sed "s/rules_mylang/rules_android_ndk/g" "$ci_file" > "$rules_android_ndk_workflows/$ci_file"
+  done
+  rm -rf $rules_template_dir
+
+  # Make a commit in rules_android_ndk
+  cd "$rules_android_ndk_dir"
+  git add .github/workflows
+  git commit -m "Pull in github workflows
+
+...from rules-template commit $rules_template_commit"
+}
+
+# If this script is invoked from the terminal, call update_github_workflows()
+if [[ "${BASH_SOURCE[0]}" == "${0}" ]]; then
+  update_github_workflows
+fi