Bug 1714690 - Remove usages of "six" in build/RunCbindgen.py....

Bug 1714690 - Remove usages of "six" in build/RunCbindgen.py. r=firefox-build-system-reviewers,glandium

Differential Revision: https://phabricator.services.mozilla.com/D178515

build/RunCbindgen.py

@@ -7,7 +7,6 @@ import subprocess
 
 import buildconfig
 import mozpack.path as mozpath
-import six
 import toml
 
 
@@ -29,11 +28,11 @@ def _run_process(args):
     env["CARGO"] = str(buildconfig.substs["CARGO"])
     env["RUSTC"] = str(buildconfig.substs["RUSTC"])
 
-    p = subprocess.Popen(args, env=env, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+    p = subprocess.Popen(
+        args, env=env, stdout=subprocess.PIPE, stderr=subprocess.PIPE, text=True
+    )
 
     stdout, stderr = p.communicate()
-    stdout = six.ensure_text(stdout)
-    stderr = six.ensure_text(stderr)
     if p.returncode != 0:
         print(stdout)
         print(stderr)