Update documentation dependencies #959

	name: Update documentation dependencies
	on:
	schedule:
	- cron: '0 0 * * *' # daily
	workflow_dispatch:
	jobs:
	update-manifest:
	runs-on: ubuntu-latest
	steps:
	- uses: actions/checkout@v2
	with:
	ssh-key: ${{ secrets.DOCUMENTER_KEY_NO_BASE64 }}
	- uses: julia-actions/setup-julia@v1
	with:
	version: '1.7' # Keep in sync with .github/workflows/ci.yml
	- name: 'Pkg.update'
	run: \|
	julia --project=. -e 'using Pkg; Pkg.update()'
	echo 'PKG_DIFF<<EOF' >> $GITHUB_ENV
	echo 'pkg> status --project --diff' >> $GITHUB_ENV
	julia --project=. -e 'using Pkg; Pkg.status(; mode=PKGMODE_PROJECT, diff=true)' >> $GITHUB_ENV
	echo '' >> $GITHUB_ENV
	echo 'pkg> status --manifest --diff' >> $GITHUB_ENV
	julia --project=. -e 'using Pkg; Pkg.status(; mode=PKGMODE_MANIFEST, diff=true)' >> $GITHUB_ENV
	echo 'EOF' >> $GITHUB_ENV
	- name: 'Create pull request'
	uses: peter-evans/create-pull-request@v3
	with:
	title: 'Automatic Pkg.update()'
	branch: 'create-pull-request/package-update'
	author: 'GitHub <[email protected]>'
	body: \|
	Automatic `Pkg.update()` with the following changes:
	```
	${{ env.PKG_DIFF }}
	```
	A preview of the build will soon be available at <https://julialogging.github.io/previews/package-update/>.
	commit-message: \|
	Automatic Pkg.update() with the following changes:

	${{ env.PKG_DIFF }}

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