A-1270 part 2: merge zstash with cache package

Author: zhming0

internal/zstash/api/client.go internal/cache/api/client.gointernal/zstash/api/client.go renamed to internal/cache/api/client.go

@@ -13,7 +13,7 @@ import (
 	"strings"
 	"time"
 
-	"github.com/buildkite/agent/v3/internal/zstash/internal/trace"
+	"github.com/buildkite/agent/v3/internal/cache/internal/trace"
 	"github.com/google/go-querystring/query"
 	"github.com/klauspost/compress/gzhttp"
 	otel "go.opentelemetry.io/otel/trace"

internal/zstash/api/client_test.go internal/cache/api/client_test.gointernal/zstash/api/client_test.go renamed to internal/cache/api/client_test.go

@@ -8,7 +8,7 @@ import (
 	"path/filepath"
 	"time"
 
-	"github.com/buildkite/agent/v3/internal/zstash/internal/trace"
+	"github.com/buildkite/agent/v3/internal/cache/internal/trace"
 	"github.com/klauspost/compress/zstd"
 	"github.com/wolfeidau/quickzip"
 	"go.opentelemetry.io/otel/attribute"

internal/zstash/archive/.gitattributes internal/cache/archive/.gitattributesinternal/zstash/archive/.gitattributes renamed to internal/cache/archive/.gitattributes

@@ -9,7 +9,7 @@ import (
 	"strings"
 	"testing"
 
-	"github.com/buildkite/agent/v3/internal/zstash/internal/trace"
+	"github.com/buildkite/agent/v3/internal/cache/internal/trace"
 )
 
 func TestBuildArchive(t *testing.T) {

internal/zstash/archive/archive.go internal/cache/archive/archive.gointernal/zstash/archive/archive.go renamed to internal/cache/archive/archive.go

@@ -9,7 +9,7 @@ import (
 	"strings"
 	"time"
 
-	"github.com/buildkite/agent/v3/internal/zstash/internal/trace"
+	"github.com/buildkite/agent/v3/internal/cache/internal/trace"
 	"github.com/klauspost/compress/zip"
 	"github.com/wolfeidau/quickzip"
 	"go.opentelemetry.io/otel/attribute"