pull changelog from corresponding branch to generate releases for Mongoose 6.x and 7.x

Author: vkarpov15

src/actions/createReleaseFromChangelog.js

@@ -6,7 +6,18 @@ module.exports = task => async function createReleaseFromChangelog(ref) {
   if (ref == null) {
     return;
   }
-  const changelog = await task.sideEffect(githubOAuth.getChangelog, {});
+  const branch = (() => {
+    if (ref.startsWith('6.')) {
+      return '6.x';
+    }
+    if (ref.startsWith('7.')) {
+      return '7.x';
+    }
+    return 'master';
+  })();
+  const changelog = await task.sideEffect(githubOAuth.getChangelog, {
+    branch
+  });
   const lines = changelog.split('\n');
   let changelogLines = null;
   for (let i = 0; i < lines.length; ++i) {

src/integrations/githubOAuth.js

@@ -47,8 +47,9 @@ module.exports = {
     return axios.post(`https://github.com/login/oauth/access_token`, body, opts).
       then(res => res.data);
   },
-  getChangelog() {
-    const url = host + '/repos/Automattic/mongoose/contents/CHANGELOG.md';
+  getChangelog(params) {
+    const branch = params && params.branch || 'master';
+    const url = host + '/repos/Automattic/mongoose/contents/CHANGELOG.md?ref=' + branch;
     const headers = {
       accept: 'application/vnd.github.v3.raw'
     };

test/createReleaseFromChangelog.test.js

@@ -31,5 +31,7 @@ describe('createReleaseFromChangelog', function() {
     const [tagAndName, body] = githubOAuth.createRelease.getCall(0).args;
     assert.equal(tagAndName, '6.1.1');
     assert.equal(body, changelog);
+    const [{ branch }] = githubOAuth.getChangelog.getCall(0).args;
+    assert.equal(branch, '6.x');
   });
 });