Upgrade to C++17/Clang/Ubuntu 24.04/newer GH action versions. #1909

	name: "build protobufs"

	on:
	push:
	branches:
	- main
	- '*-dev'
	pull_request:
	branches:
	- main
	- '*-dev'
	schedule:
	- cron: "0 0 * * *"

	jobs:
	build:
	strategy:
	matrix:
	os:
	- ubuntu-22.04
	- ubuntu-latest
	runs-on: ${{ matrix.os }}
	steps:
	- uses: actions/checkout@v4
	with:
	submodules: recursive

	- name: Mount bazel cache
	uses: actions/cache@v4
	with:
	# See https://docs.bazel.build/versions/master/output_directories.html
	path: "~/.cache/bazel"
	# Create a new cache entry whenever Bazel files change.
	# See https://docs.github.com/en/actions/guides/caching-dependencies-to-speed-up-workflows
	key: bazel-${{ runner.os }}-build-${{ hashFiles('*/.bzl', '*/.bazel*') }}
	restore-keys: \|
	bazel-${{ runner.os }}-build-

	- name: Build proto/
	run: cd proto && bazel build //... && bazel test //...

	- name: Build bazel/example/
	run: cd bazel/example/ && bazel build //...

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