fix: 如果没有上一个tag，则不需要迭代了。因为迭代会出很多过往的log，但其实并不是这次查log中需要的

Author: bearyan

src/getCommits.js

@@ -22,16 +22,14 @@ function gitLogLoop(tagCommitObjList) {
       return new Promise(async (loopResolve) => {
         const tagCommitObj = tagCommitObjList[index];
 
-        if (index > tagCommitObjList.length - 1) {
+        if (index >= tagCommitObjList.length || !tagCommitObj.previousTag) {
           loopResolve();
           return;
         }
 
         let logSelection = '';
         if (tagCommitObj.previousTag) {
           logSelection = `${tagCommitObj.tag || ''}...${tagCommitObj.previousTag}`;
-        } else {
-          logSelection = `${tagCommitObj.tag || ''}...${tagCommitObj.commits[tagCommitObj.commits.length - 1].H}`;
         }
 
         git.raw(['log', logSelection, PrettyFormats.arg], (loopErr, loopResult) => {