add missing future import

pyinst.py

@@ -1,3 +1,4 @@
+from __future__ import unicode_literals
 from PyInstaller.utils.win32.versioninfo import (
     VarStruct, VarFileInfo, StringStruct, StringTable,
     StringFileInfo, FixedFileInfo, VSVersionInfo, SetVersion,

pyinst32.py

@@ -1,3 +1,4 @@
+from __future__ import unicode_literals
 from PyInstaller.utils.win32.versioninfo import (
     VarStruct, VarFileInfo, StringStruct, StringTable,
     StringFileInfo, FixedFileInfo, VSVersionInfo, SetVersion,

scripts/update-version-workflow.py

@@ -1,3 +1,4 @@
+from __future__ import unicode_literals
 from datetime import datetime
 # import urllib.request
 

scripts/update-version.py

@@ -1,3 +1,4 @@
+from __future__ import unicode_literals
 from datetime import datetime
 import urllib.request