Merge branch 'bugfix/esp_prov_default_pop' into 'master'

Change default PoP argument of esp_prov.get_security from None to string

Closes IDFGH-5381 and IDFGH-5380

See merge request espressif/esp-idf!14353

tools/esp_prov/esp_prov.py

@@ -51,7 +51,7 @@ def on_except(err):
         print(err)
 
 
-def get_security(secver, pop=None, verbose=False):
+def get_security(secver, pop='', verbose=False):
     if secver == 1:
         return security.Security1(pop, verbose)
     elif secver == 0: