Add copyright

Author: jbowes

canonicalize.go

@@ -1,3 +1,7 @@
+// Copyright (c) 2021 James Bowes. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
 package httpsig
 
 import (

digest.go

@@ -1,3 +1,7 @@
+// Copyright (c) 2021 James Bowes. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
 package httpsig
 
 import (

httpsig.go

@@ -1,3 +1,7 @@
+// Copyright (c) 2021 James Bowes. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
 package httpsig
 
 import (

sign.go

@@ -1,3 +1,7 @@
+// Copyright (c) 2021 James Bowes. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
 package httpsig
 
 import (

standard_test.go

@@ -1,3 +1,7 @@
+// Copyright (c) 2021 James Bowes. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
 package httpsig
 
 import (

verify.go

@@ -1,3 +1,7 @@
+// Copyright (c) 2021 James Bowes. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
 package httpsig
 
 import (