fix: handle when no PR has been opened

cli.js

@@ -1,5 +1,5 @@
 #!/usr/bin/env node
-console.log('release-notes-patch -> v1.6.0 (define patch path based on data/releases.json)')
+console.log('release-notes-patch -> v1.6.1 (handle when no PR has been opened)')
 const argv = require('yargs')
   .demandOption(['token', 'owner', 'repo', 'sha', 'tag'])
   .help(false)

index.js

@@ -41,6 +41,7 @@ module.exports = async ({token, owner, repo, sha, tag, test = false} = {}) => {
   // patch release notes detail for upcoming release
   if (release.branchName === 'master') {
     const pull = await getPullBySha({owner, repo, token, sha})
+    if (!pull) return `Release notes will not be extended, because no PR found for commit ${sha} in ${owner}/${repo}. \nThis happens when someone pushes to master without opening a PR.`
     patchedReleaseNotes = addPatchToUpcomingReleaseNote({
       repo,
       releaseNote: originReleaseNote,

lib/git/get-pull-by-sha.js

@@ -11,6 +11,10 @@ module.exports = async ({owner, repo, token, sha}) => {
         'User-Agent': 'release-notes-patch'
       }
     })
+
+    // when someone pushes to master without opening a PR
+    if(res.data.length === 0) return
+
     return {
       title: res.data[0].title,
       number: res.data[0].number,