fix: call getTagHead only when necessary

lib/branches/get-tags.js

@@ -2,7 +2,7 @@ const {template, escapeRegExp} = require('lodash');
 const semver = require('semver');
 const pReduce = require('p-reduce');
 const debug = require('debug')('semantic-release:get-tags');
-const {getTags, getTagHead} = require('../../lib/git');
+const {getTags} = require('../../lib/git');
 
 module.exports = async ({cwd, env, options: {tagFormat}}, branches) => {
   // Generate a regex to parse tags formatted with `tagFormat`
@@ -21,7 +21,7 @@ module.exports = async ({cwd, env, options: {tagFormat}}, branches) => {
             return {gitTag: tag, version, channel};
           })
           .filter(({version}) => version && semver.valid(semver.clean(version)))
-          .map(async ({gitTag, ...rest}) => ({gitTag, gitHead: await getTagHead(gitTag, {cwd, env}), ...rest}))
+          .map(async ({gitTag, ...rest}) => ({gitTag, ...rest}))
       );
 
       debug('found tags for branch %s: %o', branch.name, branchTags);