update x265 encoder for aarch64

[ispysoftware]

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https://github.com/videolan/x265/archive/Release_3.5.tar.gz does not build on aarch64 I took a snapshot of the current master and patched that into my ffmpeg build script and it does build on aarch64 you can download it here if you like: https://github.com/ispysoftware/agent-install-scripts/blob/main/v2/x265_3.5.tar.gz

also you have a version mismatch here: if build "dav1d" "0.9.2"; then download "https://code.videolan.org/videolan/dav1d/-/archive/1.0.0/dav1d-1.0.0.tar.gz"