Building golang-cross-builder on m1 macbook may not work yet

[hu13]

Running

docker build --platform linux/amd64 -f Dockerfile.builder -t ghcr.io/gythialy/golang-cross-builder:v1.18 .

with the current osxcross version in this repo will lead to errors

#13 2307.6 ld: symbol(s) not found for architecture x86_64
#13 2307.6 clang: error: linker command failed with exit code 1 (use -v to see invocation)
#13 2307.6
#13 2307.6 exiting with abnormal exit code (1)
#13 2307.6 run 'OCDEBUG=1 ./build.sh' to enable debug messages
#13 2307.6
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executor failed running [/bin/sh -c UNATTENDED=yes OSX_VERSION_MIN=${OSX_VERSION_MIN} ./build.sh]: exit code: 1

The actual issue is here: tpoechtrager/osxcross#314
But adding this here to track it so when the fix gets merged, we can update our osxcross's version.