docs: add docerk file for ubuntu 20.04

dev/docker/setup-cpp-ubuntu-20.0.4.dockerfile

@@ -0,0 +1,38 @@
+#### Base Image
+FROM ubuntu:20.04 as setup-cpp-ubuntu-mingw
+
+RUN apt-get update -qq && \
+    # install latest nodejs on ubuntu 20.04
+    apt-get update -qq && \
+    apt-get install -y --no-install-recommends curl gnupg ca-certificates && \
+    mkdir -p /etc/apt/keyrings && \
+    curl -fsSL https://deb.nodesource.com/gpgkey/nodesource-repo.gpg.key | gpg --dearmor -o /etc/apt/keyrings/nodesource.gpg && \
+    echo "deb [signed-by=/etc/apt/keyrings/nodesource.gpg] https://deb.nodesource.com/node_$NODE_MAJOR.x nodistro main" | tee /etc/apt/sources.list.d/nodesource.list && \
+    apt-get update -qq && \
+    apt-get install -y --no-install-recommends nodejs && \
+    # install setup-cpp
+    npm install -g setup-cpp@v0.35.6 && \
+    # install the compiler and tools
+    setup-cpp \
+        --nala true \
+        --compiler mingw \
+        --cmake true \
+        --ninja true \
+        --task true \
+        --vcpkg true \
+        --python true \
+        --make true \
+        --cppcheck true \
+        --gcovr true \
+        --doxygen true \
+        --ccache true \
+        --powershell true && \
+    # cleanup
+    nala autoremove -y && \
+    nala autopurge -y && \
+    apt-get clean && \
+    nala clean --lists && \
+    rm -rf /var/lib/apt/lists/* && \
+    rm -rf /tmp/*
+
+ENTRYPOINT ["/bin/bash"]