Build drone for mac with m1 chip

Author: alikhil

.drone.sh

@@ -12,6 +12,7 @@ GOOS=linux   GOARCH=ppc64le go build -ldflags "-X main.version=${DRONE_TAG##v}"
 GOOS=linux   GOARCH=arm     go build -ldflags "-X main.version=${DRONE_TAG##v}" -o release/linux/arm/drone         ./drone
 GOOS=windows GOARCH=amd64   go build -ldflags "-X main.version=${DRONE_TAG##v}" -o release/windows/amd64/drone.exe ./drone
 GOOS=darwin  GOARCH=amd64   go build -ldflags "-X main.version=${DRONE_TAG##v}" -o release/darwin/amd64/drone      ./drone
+GOOS=darwin  GOARCH=arm64   go build -ldflags "-X main.version=${DRONE_TAG##v}" -o release/darwin/arm64/drone      ./drone
 
 # tar binary files prior to upload
 tar -cvzf release/drone_linux_amd64.tar.gz   -C release/linux/amd64   drone
@@ -20,6 +21,7 @@ tar -cvzf release/drone_linux_ppc64le.tar.gz -C release/linux/ppc64le drone
 tar -cvzf release/drone_linux_arm.tar.gz     -C release/linux/arm     drone
 tar -cvzf release/drone_windows_amd64.tar.gz -C release/windows/amd64 drone.exe
 tar -cvzf release/drone_darwin_amd64.tar.gz  -C release/darwin/amd64  drone
+tar -cvzf release/drone_darwin_arm64.tar.gz  -C release/darwin/arm64  drone
 
 # generate shas for tar files
 sha256sum release/*.tar.gz > release/drone_checksums.txt