fix: do not jump unstable majors unless configured to do so

lib/workers/package/versions.js

@@ -91,6 +91,13 @@ function determineUpgrades(npmDep, config) {
         stable.is(changeLogFromVersion) &&
         !stable.is(version)
     )
+    // Do not jump to a new major unstable just because the current is unstable
+    .reject(
+      version =>
+        config.ignoreUnstable &&
+        !stable.is(version) &&
+        semver.major(version) > semver.major(changeLogFromVersion)
+    )
     // Ignore versions newer than "latest", unless current version is newer than the "latest"
     .reject(
       version =>

test/workers/package/versions.spec.js

@@ -3,6 +3,7 @@ const qJson = require('../../_fixtures/npm/01.json');
 const helmetJson = require('../../_fixtures/npm/02.json');
 const coffeelintJson = require('../../_fixtures/npm/coffeelint.json');
 const webpackJson = require('../../_fixtures/npm/webpack.json');
+const nextJson = require('../../_fixtures/npm/next.json');
 
 let config;
 
@@ -346,6 +347,12 @@ describe('workers/package/versions', () => {
       const res = versions.determineUpgrades(webpackJson, config);
       expect(res).toHaveLength(3);
     });
+    it('does not jump  major unstable', () => {
+      config.currentVersion = '^4.4.0-canary.3';
+      config.pinVersions = false;
+      const res = versions.determineUpgrades(nextJson, config);
+      expect(res).toHaveLength(0);
+    });
   });
   describe('.isRange(input)', () => {
     it('rejects simple semver', () => {