MINOR: Upgrade ducktape to version 0.7.11 (#9932)

ducktape 0.7.11 fixes a bug where a unicode exception message would cause test runner to hang up and never finish.
This change should be backported to all the branches using ducktape 0.7.10

Reviewers: Konstantine Karantasis <k.karantasis@gmail.com>

tests/docker/Dockerfile

@@ -34,7 +34,7 @@ LABEL ducker.creator=$ducker_creator
 # Update Linux and install necessary utilities.
 RUN apt update && apt install -y sudo netcat iptables rsync unzip wget curl jq coreutils openssh-server net-tools vim python-pip python-dev libffi-dev libssl-dev cmake pkg-config libfuse-dev  && apt-get -y clean
 RUN python -m pip install -U pip==9.0.3;
-RUN pip install --upgrade cffi virtualenv pyasn1 boto3 pycrypto pywinrm ipaddress enum34 && pip install --upgrade ducktape==0.7.10
+RUN pip install --upgrade cffi virtualenv pyasn1 boto3 pycrypto pywinrm ipaddress enum34 && pip install --upgrade ducktape==0.7.11
 
 # Set up ssh
 COPY ./ssh-config /root/.ssh/config

tests/setup.py

@@ -51,7 +51,7 @@ setup(name="kafkatest",
       license="apache2.0",
       packages=find_packages(),
       include_package_data=True,
-      install_requires=["ducktape==0.7.10", "requests==2.22.0"],
+      install_requires=["ducktape==0.7.11", "requests==2.22.0"],
       tests_require=["pytest", "mock"],
       cmdclass={'test': PyTest},
       )