Fix lint (#7915)

* Fix lint

* Fix lint of pkg folder

pkg/backend/watch.go

@@ -1,3 +1,4 @@
+//go:build !darwin || !arm64
 // +build !darwin !arm64
 
 // Copyright 2016-2019, Pulumi Corporation.

sdk/go/common/util/cmdutil/child.go

@@ -11,6 +11,7 @@
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.
+//go:build !windows
 // +build !windows
 
 package cmdutil

sdk/nodejs/cmd/pulumi-language-nodejs/proxy_unix.go

@@ -12,7 +12,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-//+build !windows
+//go:build !windows
+// +build !windows
 
 package main
 

sdk/python/shim_unix.go

@@ -1,4 +1,5 @@
-//+build !windows
+//go:build !windows
+// +build !windows
 
 // Copyright 2020, Pulumi Corporation.
 //