Use sha256 instead of sha1

Author: DrJosh9000

.buildkite/steps/packer.sh

@@ -17,11 +17,11 @@ fi
 mkdir -p "build/"
 
 # Build a hash of packer files and the agent versions
-packer_files_sha=$(find Makefile "packer/${os}" plugins/ -type f -print0 | xargs -0 sha1sum | awk '{print $1}' | sort | sha1sum | awk '{print $1}')
-internal_files_sha=$(find go.mod go.sum internal/ -type f -print0 | xargs -0 sha1sum | awk '{print $1}' | sort | sha1sum | awk '{print $1}')
+packer_files_sha=$(find Makefile "packer/${os}" plugins/ -type f -print0 | xargs -0 sha256sum | awk '{print $1}' | sort | sha256sum | awk '{print $1}')
+internal_files_sha=$(find go.mod go.sum internal/ -type f -print0 | xargs -0 sha256sum | awk '{print $1}' | sort | sha256sum | awk '{print $1}')
 stable_agent_sha=$(curl -Lfs "https://download.buildkite.com/agent/stable/latest/${agent_binary}.sha256")
 unstable_agent_sha=$(curl -Lfs "https://download.buildkite.com/agent/unstable/latest/${agent_binary}.sha256")
-packer_hash=$(echo "$packer_files_sha" "$internal_files_sha" "$arch" "$stable_agent_sha" "$unstable_agent_sha" | sha1sum | awk '{print $1}')
+packer_hash=$(echo "$packer_files_sha" "$internal_files_sha" "$arch" "$stable_agent_sha" "$unstable_agent_sha" | sha256sum | awk '{print $1}')
 
 echo "Packer image hash for ${os}/${arch} is ${packer_hash}"
 packer_file="packer-${packer_hash}-${os}-${arch}.output"