adjust api endpoint used to retrieve previous release tag

The example I was working from was relying on the previous release being fully published and marked latest.
Since we leave experimental releases in prerelease state we need to retrieve it slightly differently.

build-scripts/generate-release-notes.js

@@ -20,7 +20,7 @@ async function main() {
   const client = github.getOctokit(token);
 
   const latestReleaseResponse = await client.request(
-    'GET /repos/{owner}/{repo}/releases/latest',
+    'GET /repos/{owner}/{repo}/releases',
     {
       owner: owner,
       repo: repo,
@@ -29,7 +29,7 @@ async function main() {
       },
     }
   );
-  const previousTag = latestReleaseResponse.data?.tag_name;
+  const previousTag = latestReleaseResponse.data?[0].tag_name;
 
   const response = await client.request(
     'POST /repos/{owner}/{repo}/releases/generate-notes',