fix: rename and delete erroneous onboarding PRs if found (#948)

lib/workers/repository/index.js

@@ -71,6 +71,21 @@ async function renovateRepository(repoConfig, token) {
         // If we can't detect any package.json then return
         if (config.packageFiles.length === 0) {
           logger.info('Cannot detect package files');
+          // istanbul ignore if
+          if (config.repoIsOnboarded === false) {
+            logger.warn('Need to delete onboarding PR');
+            const pr = await config.api.getBranchPr(config.onboardingBranch);
+            if (pr) {
+              logger.info('Found onboarding PR');
+              await config.api.updatePr(
+                pr.number,
+                'Configure Renovate - canceled',
+                'This PR was created in error and is now being deleted automatically. Sorry for the inconvenience.'
+              );
+              await config.api.deleteBranch(config.onboardingBranch);
+              throw new Error('no package files');
+            }
+          }
           return;
         }
         logger.debug(