Updated the Docker image according with the code review

linux/build-environment/Dockerfile

@@ -4,65 +4,20 @@ LABEL maintainer="d.vedenko@audacityteam.org"
 LABEL description="A build environment to check the builds for the package maintainers"
 LABEL version="3.0"
 
-ENV TZ=Europe/London
-RUN ln -snf /usr/share/zoneinfo/$TZ /etc/localtime && echo $TZ > /etc/timezone
-
-RUN apt-get update
-
-RUN apt-get install -y \
-    build-essential \
-    python3-minimal \
-    python3-pip \
-    g++-9 \
-    libstdc++-9-dev \
-    cmake \
-    git
-
-RUN pip3 install conan
-
-RUN apt-get install -y \ 
-    zlib1g-dev \
-    libgtk2.0-dev \
-    libasound2-dev \
-    libavformat-dev \
-    libjack-jackd2-dev \
-    libexpat1-dev \
-    libmp3lame-dev \
-    libsndfile-dev \
-    libsoxr-dev \
-    portaudio19-dev \
-    libsqlite3-dev \
-    libavcodec-dev \
-    libavformat-dev \
-    libavutil-dev \
-    libid3tag0-dev \
-    libmad0-dev \
-    libvamp-hostsdk3v5 \
-    libogg-dev \
-    libvorbis-dev \
-    libflac-dev \
-    libflac++-dev \
-    lv2-dev \
-    liblilv-dev \
-    libserd-dev \
-    libsord-dev \
-    libsratom-dev \
-    libsuil-dev \
-    libportmidi-dev \
-    libportsmf-dev \
-    libsbsms-dev \
-    libsoundtouch-dev \
-    libtwolame-dev \
-    libssl-dev \
-    libcurl4-openssl-dev
-
-RUN apt-get install -y libpng-dev
+RUN apt-get update && apt-get install -y dos2unix
 
 WORKDIR /audacity
 
-COPY ["build_audacity.sh", "/audacity/"]
-
+COPY ["dependencies.sh", "/audacity/"]
 # pkg-config is so broken
 COPY ["pkgconfig/*", "/usr/local/lib/pkgconfig/"]
 
-CMD ["./build_audacity.sh"]
+RUN dos2unix dependencies.sh && \
+    find /usr/local/lib/pkgconfig/ -type f -print0 | xargs -0 dos2unix
+
+RUN ["bash", "-ex", "dependencies.sh"]
+
+COPY ["entrypoint.sh", "/audacity/"]
+RUN dos2unix entrypoint.sh
+
+CMD ["bash", "-ex", "./entrypoint.sh"]