fix: correct some issues with variables

Dockerfile

-FROM openjdk:8-jdk as builder
-
 ARG PLATFORM=32
 ARG BUILD_TOOLS=32.0.0
 
+FROM openjdk:8-jdk as builder
+ARG PLATFORM
+ARG BUILD_TOOLS
+
 RUN apt-get --quiet update --yes && \
     apt-get --quiet install --yes wget tar unzip lib32stdc++6 lib32z1
 RUN wget --quiet --output-document=android-sdk.zip https://dl.google.com/android/repository/sdk-tools-linux-4333796.zip && \
@@ -19,6 +21,7 @@ RUN android-sdk-linux/tools/bin/sdkmanager \
 FROM ubuntu:focal
 ARG PLATFORM
 ARG BUILD_TOOLS
+
 COPY --from=builder /android-sdk-linux /android-sdk-linux
 RUN ln -s /android-sdk-linux/build-tools/${BUILD_TOOLS}/apksigner /usr/local/bin/apksigner