Update CI away from deprecated `save-state` and `set-output`

[dshemetov]

See context and a simple fix here. This comes up when building images. (See "Resolve Tag" in this build.)

Run baseRef="${GITHUB_REF#*/}"
Warning: The `set-output` command is deprecated and will be disabled soon. Please upgrade to using Environment Files. For more information see: https://github.blog/changelog/2022-[10](https://github.com/cmu-delphi/delphi-epidata/actions/runs/3364623430/jobs/5579258952#step:5:11)-11-github-actions-deprecating-save-state-and-set-output-commands/
Warning: The `set-output` command is deprecated and will be disabled soon. Please upgrade to using Environment Files. For more information see: https://github.blog/changelog/2022-10-11-github-actions-deprecating-save-state-and-set-output-commands/

Have until June 2023 to do this.

[dmytrotsko]

example how this was done for forcast-eval repo

[melange396]

recent changes have removed save-state but there is still some set-output used in:

delphi-epidata/.github/workflows/ci.yaml

Lines 144 to 153 in 5f23936

	echo "::set-output name=tag::$imageTag"
	echo "::set-output name=repo::ghcr.io/${{ github.repository }}"
	- name: Push Dev Tag
	run: |
	docker tag repo ${{ steps.tagname.outputs.repo }}:${{ steps.tagname.outputs.tag }}
	docker push ${{ steps.tagname.outputs.repo }}:${{ steps.tagname.outputs.tag }}
	# - name: Extract version
	# if: startsWith(github.ref, 'refs/heads/main')
	# id: extract_version
	# run: node -pe "'::set-output name=version::' + require('./package.json').version"