Refactor Dockerfile to follow GOST's new release filename syntax

Dockerfile

@@ -20,7 +20,7 @@ RUN case ${TARGETPLATFORM} in \
       "linux/arm64")   export ARCH="armv8" ;; \
       *) echo "Unsupported TARGETPLATFORM: ${TARGETPLATFORM}" && exit 1 ;; \
     esac && \
-    echo "Building for ${ARCH} with GOST ${GOST_VERSION}" &&\
+    echo "Building for ${TARGETPLATFORM} with GOST ${GOST_VERSION}" &&\
     apt-get update && \
     apt-get upgrade -y && \
     apt-get install -y curl gnupg lsb-release sudo jq ipcalc && \
@@ -30,9 +30,27 @@ RUN case ${TARGETPLATFORM} in \
     apt-get install -y cloudflare-warp && \
     apt-get clean && \
     apt-get autoremove -y && \
-    curl -LO https://github.com/ginuerzh/gost/releases/download/v${GOST_VERSION}/gost-linux-${ARCH}-${GOST_VERSION}.gz && \
-    gunzip gost-linux-${ARCH}-${GOST_VERSION}.gz && \
-    mv gost-linux-${ARCH}-${GOST_VERSION} /usr/bin/gost && \
+    MAJOR_VERSION=$(echo ${GOST_VERSION} | cut -d. -f1) && \
+    MINOR_VERSION=$(echo ${GOST_VERSION} | cut -d. -f2) && \
+    # detect if version >= 2.12.0, which uses new filename syntax
+    if [ "${MAJOR_VERSION}" -ge 3 ] || [ "${MAJOR_VERSION}" -eq 2 -a "${MINOR_VERSION}" -ge 12 ]; then \
+      NAME_SYNTAX="new" && \
+      if [ "${TARGETPLATFORM}" = "linux/arm64" ]; then \
+        ARCH="arm64"; \
+      fi && \
+      FILE_NAME="gost_${GOST_VERSION}_linux_${ARCH}.tar.gz"; \
+    else \
+      NAME_SYNTAX="legacy" && \
+      FILE_NAME="gost-linux-${ARCH}-${GOST_VERSION}.gz"; \
+    fi && \
+    echo "File name: ${FILE_NAME}" && \
+    curl -LO https://github.com/ginuerzh/gost/releases/download/v${GOST_VERSION}/${FILE_NAME} && \
+    if [ "${NAME_SYNTAX}" = "new" ]; then \
+      tar -xzf ${FILE_NAME} -C /usr/bin/ gost; \
+    else \
+      gunzip ${FILE_NAME} && \
+      mv gost-linux-${ARCH}-${GOST_VERSION} /usr/bin/gost; \
+    fi && \
     chmod +x /usr/bin/gost && \
     chmod +x /entrypoint.sh && \
     chmod +x /healthcheck/index.sh && \