Upgrade opensdk container to 22.04 and install binutils-aarch64-linux-gnu and zstd (#77)

We need both of these to be able strip the debug info out of the libraries in the SC sysroot (20.04's binutils are too old and fail on the newer `.relr.dyn` sections).

Author: Gold856

Makefile

@@ -1,5 +1,5 @@
 UBUNTU?=22.04
-OPENSDK_UBUNTU?=20.04
+OPENSDK_UBUNTU?=22.04
 DEBIAN?=bookworm
 
 DS?=trixie

opensdk/ubuntu/Dockerfile

@@ -1,4 +1,4 @@
-ARG OPENSDK_UBUNTU=20.04
+ARG OPENSDK_UBUNTU=22.04
 FROM ubuntu:${OPENSDK_UBUNTU}
 
 ENV TZ=UTC
@@ -7,9 +7,9 @@ ENV DEBIAN_FRONTEND=noninteractive
 RUN apt-get update && \
     apt-get install -y tzdata && \
     apt-get install -y \
+    binutils-aarch64-linux-gnu \
     bison \
     crossbuild-essential-amd64 \
-    crossbuild-essential-riscv64 \
     flex \
     gawk \
     libgmp-dev \
@@ -26,5 +26,6 @@ RUN apt-get update && \
     sudo \
     texinfo \
     wget \
-    zip && \
+    zip \
+    zstd && \
   rm -rf /var/lib/apt/lists/*