fix: add all modified files to git index with git add .

lib/gitWorkflow.js

@@ -105,7 +105,7 @@ class GitWorkflow {
       debug('Detected files modified by tasks:')
       debug(modifiedFiles)
       debug('Adding files to index...')
-      await this.execGit(['add', modifiedFiles])
+      await this.execGit(['add', '.'])
       debug('Done adding files to index!')
     }
 

test/runAll.unmocked.spec.js

@@ -129,17 +129,21 @@ describe('runAll', () => {
   })
 
   it('Should commit entire staged file when no errors and linter modifies file', async () => {
-    // Stage ugly file
+    // Stage multiple ugly files
     await appendFile('test.js', testJsFileUgly)
     await execGit(['add', 'test.js'])
 
+    await appendFile('test2.js', testJsFileUgly)
+    await execGit(['add', 'test2.js'])
+
     // Run lint-staged with `prettier --write` and commit pretty file
     await gitCommit(fixJsConfig)
 
     // Nothing is wrong, so a new commit is created and file is pretty
     expect(await execGit(['rev-list', '--count', 'HEAD'])).toEqual('2')
     expect(await execGit(['log', '-1', '--pretty=%B'])).toMatch('test')
     expect(await readFile('test.js')).toEqual(testJsFilePretty)
+    expect(await readFile('test2.js')).toEqual(testJsFilePretty)
   })
 
   it('Should fail to commit entire staged file when errors from linter', async () => {