release/dist: add forgotten license headers

Signed-off-by: David Anderson <danderson@tailscale.com>

cmd/dist/dist.go

@@ -1,3 +1,6 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
 // The dist command builds Tailscale release packages for distribution.
 package main
 

release/dist/cli/cli.go

@@ -1,3 +1,6 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
 // Package cli provides the skeleton of a CLI for building release packages.
 package cli
 

release/dist/dist.go

@@ -1,3 +1,6 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
 // Package dist is a release artifact builder library.
 package dist
 

release/dist/memoize.go

@@ -1,3 +1,6 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
 package dist
 
 import (

release/dist/unixpkgs/pkgs.go

@@ -1,3 +1,6 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
 // Package unixpkgs contains dist Targets for building unix Tailscale packages.
 package unixpkgs
 

release/dist/unixpkgs/targets.go

@@ -1,3 +1,6 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
 package unixpkgs
 
 import (