ICU-22721 Add workflow that enforces required checks #1

	# Copyright (C) 2016 and later: Unicode, Inc. and others.
	# License & terms of use: http://www.unicode.org/copyright.html
	#
	# GitHub Actions workflow to ensure all required checks pass when they are attempted.
	# In other words, many checks are conditionally run, so use this workflow as a workaround
	# to a limitation in Github Actions in how required checks are enforced. Instead of
	# Github's naive behavior currently, this workflow only asserts that status=passing on
	# checks when they are run.

	name: Wait for Required Checks

	on:
	push:
	branches:
	- main
	- 'maint/maint*'
	pull_request:
	branches: '**'

	jobs:
	enforce-all-checks:
	runs-on: ubuntu-latest
	permissions:
	checks: read
	steps:
	- name: Wait for Triggered Required GH Checks
	uses: poseidon/wait-for-status-checks@6988432d64ad3f9c2608db4ca16fded1b7d36ead # v0.5.0
	with:
	token: ${{ secrets.GITHUB_TOKEN }}
	# This is one large regex. The YAML `>-` concatenates while removing
	# whitespace between lines and prevents an extra new line from being
	# added at the end.
	# The regex syntax uses `\|` to indicate "alternation" (multiple possible options)
	# so don't end the last line/option with a `\|` symbol.
	match_pattern: >-
	Test build of User Guide docs\|
	copyright-scan\|
	valid-UTF-8-and-no-BOM-check\|
	icu4j-.*\|
	icu4c-.*\|
	gcc-.*\|
	clang-.*\|
	run-with-stubdata\|
	u-.*\|
	lstm-test\|
	adaboost-test\|
	testmap\|
	internal-header-compilation\|
	valid-UTF-8-and-no-BOM-check\|
	uconfig-unit-tests.*\|
	unicode-update-tools\|
	lstm-icu4j.*\|
	adaboost-icu4j.*\|
	env-test.*

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