GitHub action for release notices on Slack

Signed-off-by: Cary Phillips <[email protected]>

.github/workflows/release-notice.yml

@@ -0,0 +1,24 @@
+jobs:
+  publish:
+    runs-on: ubuntu-latest
+    timeout-minutes: 5
+
+    steps:
+    - name: 'Notify Slack #release-announcements'
+      id: slack1
+      with:
+        project_name: "OpenEXR"
+        slack_bot_token: ${{ secrets.SLACK_BOT_TOKEN }}
+        slack_channel: "#release-announcements"
+        project_logo: "https://artwork.aswf.io/other/aswf/text/aqua/aswf-text-aqua.png"
+      uses: jmertic/slack-release-notifier@main
+
+    - name: 'Notify Slack #openexr'
+      id: slack2
+      with:
+        project_name: "OpenEXR"
+        slack_bot_token: ${{ secrets.SLACK_BOT_TOKEN }}
+        slack_channel: "#openexr"
+        project_logo: "https://artwork.aswf.io/other/aswf/text/aqua/aswf-text-aqua.png"
+      uses: jmertic/slack-release-notifier@main
+