perl: warning: Setting locale failed.

[zalyoung]

What I'd like to do:
Solve the below warning during Docker image build.

perl: warning: Setting locale failed.
perl: warning: Please check that your locale settings:
	LANGUAGE = (unset),
	LC_ALL = (unset),
	LANG = "en_US.utf8"
    are supported and installed on your system.
perl: warning: Falling back to the standard locale ("C").
locale: Cannot set LC_CTYPE to default locale: No such file or directory
locale: Cannot set LC_MESSAGES to default locale: No such file or directory
locale: Cannot set LC_ALL to default locale: No such file or directory
debconf: delaying package configuration, since apt-utils is not installed

Steps I've done:

# git clone https://github.com/gocd/docker-gocd-agent-debian-8.git
# cd docker-gocd-agent-debian-8
# docker build -t docker-gocd-agent-debian-8 .

Questions:
I found the my GoCD agent pod can not support Chinese characters during Gradle build

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':account-management-service:generateGitProperties'.
> Malformed input or input contains unmappable characters: /godata/pipelines/a-management-gocd-test/app/a-management-service/src/main/resources/xlxs feature toogle steUp ??????.md

Is this problem related to the warning during the image build?