Corriger les warnings dans le Dockerfile de tests

Warning: LegacyKeyValueFormat

Dockerfile.test

@@ -1,6 +1,6 @@
 FROM ubuntu:22.04
 
-ENV DEBIAN_FRONTEND noninteractive
+ENV DEBIAN_FRONTEND=noninteractive
 
 RUN apt update \
  && apt install ca-certificates python3 python3-pip php8.1-cli php8.1-xml sslscan -y --no-install-recommends \
@@ -15,9 +15,9 @@ RUN python3 -m pip install --upgrade pip
 RUN pip3 install -U setuptools --no-cache-dir
 RUN mkdir /usr/src/app
 
-ENV LANG en_US.UTF-8
-ENV LANGUAGE en_US:en
-ENV LC_ALL en_US.UTF-8
+ENV LANG=en_US.UTF-8
+ENV LANGUAGE=en_US:en
+ENV LC_ALL=en_US.UTF-8
 
 WORKDIR /usr/src/app