add fly.io PR review apps (#9069)

* add fly.io PR review apps

* add fly.toml to dockerignore

* merge branch instead of applying diff

---------

Co-authored-by: repo-ranger[bot] <39074581+repo-ranger[bot]@users.noreply.github.com>

.github/scripts/cleanup-review-apps.sh

@@ -0,0 +1,10 @@
+#!/bin/bash
+
+set -euxo pipefail
+
+apps=$(flyctl apps list --json | jq -r .[].ID | grep -E "pr-[0-9]+-badges-shields") || exit 0
+
+for app in $apps
+do
+  flyctl apps destroy "$app" -y
+done

.github/scripts/deploy-review-app.sh

@@ -0,0 +1,35 @@
+#!/bin/bash
+
+set -euxo pipefail
+
+app="pr-$PR_NUMBER-badges-shields"
+region="ewr"
+org="shields-io"
+
+# Get PR JSON from the API
+# This will fail if $PR_NUMBER is not a valid PR
+pr_json=$(curl --fail "https://api.github.com/repos/badges/shields/pulls/$PR_NUMBER")
+
+# Attempt to apply the PR diff to the target branch
+# This will fail if it does not merge cleanly
+git config user.name "actions[bot]"
+git config user.email "actions@users.noreply.github.com"
+git fetch origin "pull/$PR_NUMBER/head:pr-$PR_NUMBER"
+git merge "pr-$PR_NUMBER"
+
+# If the app does not already exist, create it
+if ! flyctl status --app "$app"; then
+  flyctl launch --no-deploy --copy-config --name "$app" --region "$region" --org "$org"
+  echo $SECRETS | tr " " "\n" | flyctl secrets import --app "$app"
+fi
+
+# Deploy
+flyctl deploy --app "$app" --region "$region"
+
+# Post a comment on the PR
+app_url=$(flyctl status --app "$app" --json | jq -r .Hostname)
+comment_url=$(echo "$pr_json" | jq .comments_url -r)
+curl "$comment_url" \
+    -X POST \
+    -H "Authorization: token $GITHUB_TOKEN" \
+    --data "{\"body\":\"🚀 Updated review app: https://$app_url\"}"