all: use spdx license headers

Author: willnorris

LICENSE

@@ -1,4 +1,4 @@
-Copyright 2014, Google Inc. All rights reserved.
+Copyright (c) 2014 Google, Will Norris
 
 Redistribution and use in source and binary forms, with or without
 modification, are permitted provided that the following conditions are
@@ -20,8 +20,8 @@ LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
-LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,           
-DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY           
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

cmd/webmention/main.go

@@ -1,8 +1,5 @@
-// Copyright 2014 Google Inc. All rights reserved.
-//
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file or at
-// https://developers.google.com/open-source/licenses/bsd
+// Copyright (c) The webmention project authors.
+// SPDX-License-Identifier: BSD-3-Clause
 
 // The webmention binary is a command line utility for sending webmentions to
 // the URLs linked to by a given webpage.

html.go

@@ -1,8 +1,5 @@
-// Copyright 2014 Google Inc. All rights reserved.
-//
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file or at
-// https://developers.google.com/open-source/licenses/bsd
+// Copyright (c) The webmention project authors.
+// SPDX-License-Identifier: BSD-3-Clause
 
 package webmention
 

html_test.go

@@ -1,8 +1,5 @@
-// Copyright 2014 Google Inc. All rights reserved.
-//
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file or at
-// https://developers.google.com/open-source/licenses/bsd
+// Copyright (c) The webmention project authors.
+// SPDX-License-Identifier: BSD-3-Clause
 
 package webmention
 

http.go

@@ -1,8 +1,5 @@
-// Copyright 2014 Google Inc. All rights reserved.
-//
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file or at
-// https://developers.google.com/open-source/licenses/bsd
+// Copyright (c) The webmention project authors.
+// SPDX-License-Identifier: BSD-3-Clause
 
 package webmention
 

http_test.go

@@ -1,8 +1,5 @@
-// Copyright 2014 Google Inc. All rights reserved.
-//
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file or at
-// https://developers.google.com/open-source/licenses/bsd
+// Copyright (c) The webmention project authors.
+// SPDX-License-Identifier: BSD-3-Clause
 
 package webmention
 

webmention.go

@@ -1,8 +1,5 @@
-// Copyright 2014 Google Inc. All rights reserved.
-//
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file or at
-// https://developers.google.com/open-source/licenses/bsd
+// Copyright (c) The webmention project authors.
+// SPDX-License-Identifier: BSD-3-Clause
 
 // Package webmention provides functions for discovering the webmention
 // endpoint for URLs, and sending webmentions according to

webmention_test.go

@@ -1,8 +1,5 @@
-// Copyright 2014 Google Inc. All rights reserved.
-//
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file or at
-// https://developers.google.com/open-source/licenses/bsd
+// Copyright (c) The webmention project authors.
+// SPDX-License-Identifier: BSD-3-Clause
 
 package webmention