GHA: Send release notification mail

Rather than manually crafting what ends up being nearly identical
release e-mails, do it automatically whenever a release is created.

Note: At the time of this commit, there is a possible race condition
with the `mac-pkg.yml` workflow, since it runs in parallel.  It could
fail, or fail to complete prior to the e-mail content being generated.
This should be unlikely, if `release-artifacts.yml` goes through and
compiles every artifact, but it's not guaranteed.

Signed-off-by: Chris Evich <cevich@redhat.com>

.github/workflows/release-artifacts.yml

@@ -31,6 +31,7 @@ jobs:
         echo "::group::Event JSON"
         jq --color-output "." ${{ github.event_path }}""
         echo "::endgroup::"
+
     - name: Determine Version
       id: getversion
       run: |
@@ -105,7 +106,6 @@ jobs:
         steps.actual_dryrun.outputs.dryrun == 'true'
       uses: actions/checkout@v4
       with:
-        repository: containers/podman
         ref: ${{steps.getversion.outputs.version}}
 
     - name: Set up Go
@@ -185,6 +185,7 @@ jobs:
           release/*
 
     - name: Upload to Release
+      id: upload
       if: >-
         steps.check.outputs.buildartifacts == 'true' &&
         steps.actual_dryrun.outputs.dryrun == 'false'
@@ -196,6 +197,9 @@ jobs:
         gh release upload ${{steps.getversion.outputs.version}} release/*.zip release/*.tar.gz
         gh release upload ${{steps.getversion.outputs.version}} --clobber shasums
 
+        # WARNING: This should only be set when 'notification' job should be triggered
+        echo "complete=true" >> $GITHUB_OUTPUT
+
     - name: Trigger Windows Installer
       if: >-
           steps.check.outputs.windows_amd == 'true' ||
@@ -204,3 +208,46 @@ jobs:
         GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
       run: |
         gh workflow run upload-win-installer.yml -f version=${{steps.getversion.outputs.version}} -f dryrun=false
+    outputs:
+      uploaded: ${{ steps.upload.outputs.complete }}
+      version: ${{ steps.getversion.outputs.version }}
+
+  notification:
+    if: needs.build.outputs.uploaded == 'true'
+    runs-on: ubuntu-22.04
+    needs: build
+    steps:
+      - name: Format release email
+        env:
+          VERSION: ${{ needs.build.outputs.version }}
+        run: |
+          cat <<EOF>email_body.txt
+          Hi all,
+
+          Podman $VERSION is now available.  You may view the full details at
+          https://github.com/${{ github.repository }}/releases/tag/$VERSION
+
+          Release Notes:
+          --------------
+          EOF
+
+          echo ${{ secrets.GITHUB_TOKEN }} | gh auth login --with-token
+          gh release view $VERSION \
+            --repo ${{ github.repository }} --json=body --jq '.body' >> email_body.txt
+
+      # If job fails, permit operator to observe contents in case helpful.
+      - name: Provide release e-mail contents for examination
+        run: cat email_body.txt
+
+      - name: Send release notification e-mail
+        # Ref: https://github.com/dawidd6/action-send-mail
+        uses: dawidd6/action-send-mail@v3.12.0
+        with:
+          server_address: ${{secrets.ACTION_MAIL_SERVER}}
+          server_port: 465
+          username: ${{secrets.ACTION_MAIL_USERNAME}}
+          password: ${{secrets.ACTION_MAIL_PASSWORD}}
+          subject: Podman ${{ needs.build.outputs.version }} Released
+          to: Podman List <podman@lists.podman.io>
+          from: ${{secrets.ACTION_MAIL_SENDER}}
+          body: file://./email_body.txt