feat: pass cwd and env context to plugins

- Allow to run semantic-release (via API) from anywhere passing the current working directory.
- Allows to simplify the tests and to run them in parallel in both the core and plugins.

lib/get-commits.js

@@ -5,13 +5,11 @@ const debug = require('debug')('semantic-release:get-commits');
 /**
  * Retrieve the list of commits on the current branch since the commit sha associated with the last release, or all the commits of the current branch if there is no last released version.
  *
- * @param {String} gitHead The commit sha associated with the last release.
- * @param {String} branch The branch to release from.
- * @param {Object} logger Global logger.
+ * @param {Object} context semantic-release context.
  *
  * @return {Promise<Array<Object>>} The list of commits on the branch `branch` since the last release.
  */
-module.exports = async (gitHead, branch, logger) => {
+module.exports = async ({cwd, env, lastRelease: {gitHead}, logger}) => {
   if (gitHead) {
     debug('Use gitHead: %s', gitHead);
   } else {
@@ -19,13 +17,13 @@ module.exports = async (gitHead, branch, logger) => {
   }
 
   Object.assign(gitLogParser.fields, {hash: 'H', message: 'B', gitTags: 'd', committerDate: {key: 'ci', type: Date}});
-  const commits = (await getStream.array(gitLogParser.parse({_: `${gitHead ? gitHead + '..' : ''}HEAD`}))).map(
-    commit => {
-      commit.message = commit.message.trim();
-      commit.gitTags = commit.gitTags.trim();
-      return commit;
-    }
-  );
+  const commits = (await getStream.array(
+    gitLogParser.parse({_: `${gitHead ? gitHead + '..' : ''}HEAD`}, {cwd, env: {...process.env, ...env}})
+  )).map(commit => {
+    commit.message = commit.message.trim();
+    commit.gitTags = commit.gitTags.trim();
+    return commit;
+  });
   logger.log('Found %s commits since last release', commits.length);
   debug('Parsed commits: %o', commits);
   return commits;