dl: add go1.5.4, go1.6.4, and go1.7.6

Fixes golang/go#37156

Change-Id: Ic39a0a67d7ac86f85de8a6b56ff5607426523c78
Reviewed-on: https://go-review.googlesource.com/c/dl/+/221618
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
diff --git a/go1.5.4/main.go b/go1.5.4/main.go
new file mode 100644
index 0000000..da5a857
--- /dev/null
+++ b/go1.5.4/main.go
@@ -0,0 +1,24 @@
+// Copyright 2020 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// The go1.5.4 command runs the go command from Go 1.5.4.
+//
+// To install, run:
+//
+//     $ go get golang.org/dl/go1.5.4
+//     $ go1.5.4 download
+//
+// And then use the go1.5.4 command as if it were your normal go
+// command.
+//
+// See the release notes at https://golang.org/doc/devel/release.html#go1.5.minor
+//
+// File bugs at https://golang.org/issues/new
+package main
+
+import "golang.org/dl/internal/version"
+
+func main() {
+	version.Run("go1.5.4")
+}
diff --git a/go1.6.4/main.go b/go1.6.4/main.go
new file mode 100644
index 0000000..2cf53c2
--- /dev/null
+++ b/go1.6.4/main.go
@@ -0,0 +1,24 @@
+// Copyright 2020 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// The go1.6.4 command runs the go command from Go 1.6.4.
+//
+// To install, run:
+//
+//     $ go get golang.org/dl/go1.6.4
+//     $ go1.6.4 download
+//
+// And then use the go1.6.4 command as if it were your normal go
+// command.
+//
+// See the release notes at https://golang.org/doc/devel/release.html#go1.6.minor
+//
+// File bugs at https://golang.org/issues/new
+package main
+
+import "golang.org/dl/internal/version"
+
+func main() {
+	version.Run("go1.6.4")
+}
diff --git a/go1.7.6/main.go b/go1.7.6/main.go
new file mode 100644
index 0000000..5c0b1e5
--- /dev/null
+++ b/go1.7.6/main.go
@@ -0,0 +1,24 @@
+// Copyright 2020 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// The go1.7.6 command runs the go command from Go 1.7.6.
+//
+// To install, run:
+//
+//     $ go get golang.org/dl/go1.7.6
+//     $ go1.7.6 download
+//
+// And then use the go1.7.6 command as if it were your normal go
+// command.
+//
+// See the release notes at https://golang.org/doc/devel/release.html#go1.7.minor
+//
+// File bugs at https://golang.org/issues/new
+package main
+
+import "golang.org/dl/internal/version"
+
+func main() {
+	version.Run("go1.7.6")
+}