fix: add baseBranch to return value in getPrInfo (#60)

Author: s-yoshika

index.js

@@ -830,7 +830,8 @@ class BitbucketScm extends Scm {
                 name: `PR-${pr.id}`,
                 ref: pr.source.branch.name,
                 sha: pr.source.commit.hash,
-                url: pr.links.html.href
+                url: pr.links.html.href,
+                baseBranch: pr.source.branch.name
             };
         });
     }

test/index.test.js

@@ -1909,7 +1909,8 @@ describe('index', function () {
                         name: 'PR-1',
                         ref: 'testbranch',
                         sha: 'hashValue',
-                        url: 'https://api.bitbucket.org/2.0/repositories/repoId/pullrequests/1'
+                        url: 'https://api.bitbucket.org/2.0/repositories/repoId/pullrequests/1',
+                        baseBranch: 'testbranch'
                     });
                 });
         });