Fix bin/jp-compliance: specify encode for compatibility in Python3

This avoids following error in Python3: “TypeError: a bytes-like object is required, not 'str’”

Author: tmshn

bin/jp-compliance

@@ -127,7 +127,8 @@ class ComplianceTestRunner(object):
         command.append(test_case['expression'])
         process = subprocess.Popen(command, stdout=subprocess.PIPE,
                                    stderr=subprocess.PIPE,
-                                   stdin=subprocess.PIPE)
+                                   stdin=subprocess.PIPE,
+                                   encoding='utf-8')
         process.stdin.write(json.dumps(test_case['given']))
         process.stdin.flush()
         stdout, stderr = process.communicate()