fix: move pull request header and footer to the correct location in release configuration

Author: dermatz

release-please-config.json

@@ -1,11 +1,11 @@
 {
   "$schema": "https://raw.githubusercontent.com/googleapis/release-please/main/schemas/config.json",
+  "pull-request-header": "📦 A new release is almost ready to be published!",
+  "pull-request-footer": "If you have any questions about the release, please contact the maintainers.",
   "packages": {
     ".": {
       "release-type": "node",
       "changelog-path": "CHANGELOG.md",
-      "pull-request-header": "📦 A new release is almost ready to be published!",
-      "pull-request-footer": "If you have any questions about the release, please contact the maintainers.",
       "include-v-in-tag": false,
       "include-component-in-tag": false
     }