add discord release action

Update community_release_actions.yml

Author: ZacCranko

.github/workflows/community_release_actions.yml

@@ -0,0 +1,31 @@
+name: Release Actions
+
+on:
+  release:
+    types: [published]
+
+jobs:
+  discord_release:
+    if: github.repository_owner == 'jax-ml'
+    runs-on: ubuntu-latest
+    steps:
+      - name: Get release URL
+        id: get-release-url
+        run: |
+          URL="https://docs.jax.dev/en/latest/changelog.html"
+          echo "::set-output name=URL::$URL"
+      - name: Get content
+        uses: 2428392/gh-truncate-string-action@b3ff790d21cf42af3ca7579146eedb93c8fb0757 # v1.4.1
+        id: get-content
+        with:
+          stringToTruncate: |
+            JAX [${{ github.event.release.tag_name }}](<${{ steps.get-release-url.outputs.URL }}>) was just released!
+
+            ${{ github.event.release.body }}
+          maxLength: 2000
+          truncationSymbol: "..."
+      - name: Discord Webhook Action
+        uses: tsickert/discord-webhook@c840d45a03a323fbc3f7507ac7769dbd91bfb164 # v5.3.0
+        with:
+          webhook-url: ${{ secrets.DISCORD_WEBHOOK_URL }}
+          content: ${{ steps.get-content.outputs.string }}