pypi_formula_mappings: remove six exclusion from formulae that don't use it

pypi_formula_mappings.json

@@ -435,9 +435,6 @@
   "pip-audit": {
     "exclude_packages": ["six", "Pygments"]
   },
-  "pipenv": {
-    "exclude_packages": ["six"]
-  },
   "pipgrip": {
     "exclude_packages": ["six"],
     "extra_packages": ["wheel"]
@@ -463,9 +460,6 @@
   "proselint": {
     "exclude_packages": ["six"]
   },
-  "protobuf": {
-    "exclude_packages": ["six"]
-  },
   "prowler": {
     "exclude_packages": ["six", "tabulate", "typing-extensions", "PyYAML"]
   },
@@ -501,9 +495,6 @@
   "pyvim": {
     "exclude_packages": ["six"]
   },
-  "pywhat": {
-    "exclude_packages": ["six"]
-  },
   "rbtools": {
     "exclude_packages": ["six", "typing-extensions"]
   },
@@ -658,9 +649,6 @@
   "vint": {
     "exclude_packages": ["PyYAML"]
   },
-  "virtualenv": {
-    "exclude_packages": ["six"]
-  },
   "virtualenvwrapper": {
     "exclude_packages": ["six", "virtualenv"]
   },