Update stable rustc #4

	name: Update stable rustc
	on:
	schedule:
	- cron: "0 0 * * 6" # runs every Saturday 00:00
	workflow_dispatch: # allows manual triggering
	jobs:
	format:
	name: Update stable rustc
	runs-on: ubuntu-latest
	steps:
	- uses: actions/checkout@v4
	- uses: dtolnay/rust-toolchain@stable
	- name: Update rust.yml to use latest stable
	run: \|
	set -x
	# Extract the date from whatever version of the compiler dtolnay/rust-toolchain gives us.
	RUSTC_VERSION=$(rustc --verbose --version \| sed -ne 's/^release: //p')
	# Update the version in the reference file.
	echo "${RUSTC_VERSION}" > rustc-version
	echo "rustc_version=${RUSTC_VERSION}" >> $GITHUB_ENV
	# In case of no new version don't make an empty PR.
	if ! git diff --exit-code > /dev/null; then
	echo "Updated rustc. Opening PR."
	echo "changes_made=true" >> $GITHUB_ENV
	else
	echo "Attempted to update rustc but the latest stable date did not change. Not opening any PR."
	echo "changes_made=false" >> $GITHUB_ENV
	fi
	- name: Create Pull Request
	if: env.changes_made == 'true'
	uses: peter-evans/create-pull-request@v6
	with:
	token: ${{ secrets.CREATE_PR_TOKEN }}
	author: Update Rustc Bot <bot@example.com>
	committer: Update Rustc Bot <bot@example.com>
	title: Automated weekly update to rustc (to ${{ env.rustc_version }})
	body: \|
	Automated update to Github CI workflow `rust.yml` by [create-pull-request](https://github.com/peter-evans/create-pull-request) GitHub action
	commit-message: Automated update to Github CI to rustc ${{ env.rustc_version }}
	branch: create-pull-request/weekly-stable-update

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