KAFKA-17540: Create script for updating a reference of latest cached trunk commit (#17204)

Uses the `gh` CLI to find the latest trunk commit which has been cached by GitHub actions. By basing PRs off of this
ref rather than HEAD, we will see fewer cache misses in our CI builds.

Reviewers: Chia-Ping Tsai <chia7712@gmail.com>, David Arthur <mumrah@gmail.com>

committer-tools/update-cache.sh

@@ -0,0 +1,47 @@
+#!/bin/bash
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you 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.
+
+if ! git config --get alias.update-cache > /dev/null; then
+  printf '\e[36m%s\n\n  %s\n\e[0m\n' \
+    'Hint: you can create a Git alias to execute this script. Example:' \
+    "git config alias.update-cache '!bash $(realpath "$0")'"
+fi
+
+key="$(
+  gh cache list \
+    --key 'gradle-home-v1|Linux-X64|test' \
+    --sort 'created_at' \
+    --limit 1 \
+    --json 'key' \
+    --jq '.[].key'
+)"
+
+sha="$(cut -d '-' -f 5 <<< "$key")"
+
+if ! git show "$sha" &> /dev/null; then
+  printf '\e[33m%s\n%s\e[0m\n' \
+  "Cannot update 'trunk-cached' because SHA $sha" \
+  "does not exist locally. Please update your remote and try again."
+else
+  if git branch -f trunk-cached "$sha" &> /dev/null; then
+    rel_date="$(git show --no-patch $sha --date=relative --pretty=format:'%cr')"
+    printf '%s\n' "Local branch 'trunk-cached' successfully updated to $(head -c 10 <<< "$sha") (from $rel_date)."
+  else
+    printf '\e[31m%s\e[0m\n' "Failed to update ref for 'trunk-cached' and commit $(head -c 10 <<< "$sha")."
+  fi
+fi