Fix readme entry for addFileAttribute

fixes #112

README.md

@@ -65,7 +65,7 @@ Reporter options should also be strings exception for suiteNameTemplate, classNa
 | `JEST_JUNIT_CLASSNAME` | `classNameTemplate` | Template string for the `classname` attribute of `<testcase>`. | `"{classname} {title}"` | `{classname}`, `{title}`, `{filepath}`, `{filename}`, `{displayName}`
 | `JEST_JUNIT_TITLE` | `titleTemplate` | Template string for the `name` attribute of `<testcase>`. | `"{classname} {title}"` | `{classname}`, `{title}`, `{filepath}`, `{filename}`, `{displayName}`
 | `JEST_JUNIT_ANCESTOR_SEPARATOR` | `ancestorSeparator` | Character(s) used to join the `describe` blocks. | `" "` | N/A
-| `JEST_JUNIT_ADD_FILE_ATTRIBUTE` | `addFileAttribute` | Add file attribute to the output. This config is primarily for Circle CI. This setting provides richer details but may break on other CI platforms. | `false` | N/A
+| `JEST_JUNIT_ADD_FILE_ATTRIBUTE` | `addFileAttribute` | Add file attribute to the output. This config is primarily for Circle CI. This setting provides richer details but may break on other CI platforms. Must be a string. | `"false"` | N/A
 | `JEST_JUNIT_INCLUDE_CONSOLE_OUTPUT` | `includeConsoleOutput` | Adds console output to any testSuite that generates stdout during a test run. | `false` | N/A
 | `JEST_JUNIT_INCLUDE_SHORT_CONSOLE_OUTPUT` | `includeShortConsoleOutput` | Adds short console output (only message value) to any testSuite that generates stdout during a test run. | `false` | N/A
 | `JEST_USE_PATH_FOR_SUITE_NAME` | `usePathForSuiteName` | **DEPRECATED. Use `suiteNameTemplate` instead.** Use file path as the `name` attribute of `<testsuite>` | `"false"` | N/A