Merge upstream changes from Marlin 2.1.1

buildroot/share/PlatformIO/scripts/random-bin.py

@@ -2,8 +2,8 @@
 # random-bin.py
 # Set a unique firmware name based on current date and time
 #
-Import("env")
-
-from datetime import datetime
-
-env['PROGNAME'] = datetime.now().strftime("firmware-%Y%m%d-%H%M%S")
+import pioutil
+if pioutil.is_pio_build():
+	from datetime import datetime
+	Import("env")
+	env['PROGNAME'] = datetime.now().strftime("firmware-%Y%m%d-%H%M%S")