build: include Darwin ARM64 build

[maxdanilov]

Currently we're only building for Darwin AMD64 (x64), but the default architecture for recent Macbooks is ARM64.
This PR includes a new binary to be built for ARM64 architecture (binary name zbctl.darwin-arm64). The AMD64 flavor will be built as zbctl.darwin-amd64.

---

Tested by running locally:

./cmd/zbctl/build.sh

+ OS=(linux windows darwin darwin)
+ ARCH=(amd64 amd64 amd64 arm64)
+ BINARY=(zbctl zbctl.exe zbctl.darwin-amd64 zbctl.darwin-arm64)
++ dirname ./cmd/zbctl/build.sh
+ SRC_DIR=./cmd/zbctl
+ DIST_DIR=./cmd/zbctl/dist
+ VERSION=development
++ git rev-parse HEAD
+ COMMIT=173f92a824dfa6508a6311d98a00c579b9f9690b
+ mkdir -p ./cmd/zbctl/dist
+ rm -rf ./cmd/zbctl/dist/zbctl ./cmd/zbctl/dist/zbctl.darwin-amd64 ./cmd/zbctl/dist/zbctl.darwin-arm64 ./cmd/zbctl/dist/zbctl.exe
+ for i in '"${!OS[@]}"'
+ '[' 0 -eq 0 ']'
+ for i in '"${!OS[@]}"'
+ '[' 0 -eq 0 ']'
+ CGO_ENABLED=0
+ GOOS=linux
+ GOARCH=amd64
+ go build -a -tags netgo -ldflags '-w -X github.com/camunda-community-hub/zeebe-client-go/v8/cmd/zbctl/internal/commands.Version=development -X github.com/camunda-community-hub/zeebe-client-go/v8/cmd/zbctl/internal/commands.Commit=173f92a824dfa6508a6311d98a00c579b9f9690b' -o ./cmd/zbctl/dist/zbctl ./cmd/zbctl/main.go
+ for i in '"${!OS[@]}"'
+ '[' 0 -eq 0 ']'
+ CGO_ENABLED=0
+ GOOS=windows
+ GOARCH=amd64
+ go build -a -tags netgo -ldflags '-w -X github.com/camunda-community-hub/zeebe-client-go/v8/cmd/zbctl/internal/commands.Version=development -X github.com/camunda-community-hub/zeebe-client-go/v8/cmd/zbctl/internal/commands.Commit=173f92a824dfa6508a6311d98a00c579b9f9690b' -o ./cmd/zbctl/dist/zbctl.exe ./cmd/zbctl/main.go
+ for i in '"${!OS[@]}"'
+ '[' 0 -eq 0 ']'
+ CGO_ENABLED=0
+ GOOS=darwin
+ GOARCH=amd64
+ go build -a -tags netgo -ldflags '-w -X github.com/camunda-community-hub/zeebe-client-go/v8/cmd/zbctl/internal/commands.Version=development -X github.com/camunda-community-hub/zeebe-client-go/v8/cmd/zbctl/internal/commands.Commit=173f92a824dfa6508a6311d98a00c579b9f9690b' -o ./cmd/zbctl/dist/zbctl.darwin-amd64 ./cmd/zbctl/main.go
+ wait
+ CGO_ENABLED=0
+ GOOS=darwin
+ GOARCH=arm64
+ go build -a -tags netgo -ldflags '-w -X github.com/camunda-community-hub/zeebe-client-go/v8/cmd/zbctl/internal/commands.Version=development -X github.com/camunda-community-hub/zeebe-client-go/v8/cmd/zbctl/internal/commands.Commit=173f92a824dfa6508a6311d98a00c579b9f9690b' -o ./cmd/zbctl/dist/zbctl.darwin-arm64 ./cmd/zbctl/main.go

result:

ls -l cmd/zbctl/dist
total 103776
-rwxr-xr-x  1 maxim.danilov  staff  13182711 Oct 25 21:14 zbctl
-rwxr-xr-x  1 maxim.danilov  staff  13373408 Oct 25 21:14 zbctl.darwin-amd64
-rwxr-xr-x  1 maxim.danilov  staff  13020274 Oct 25 21:14 zbctl.darwin-arm64
-rwxr-xr-x  1 maxim.danilov  staff  13550592 Oct 25 21:14 zbctl.exe

[megglos]

LGTM! Thank you!