internal/history: document upcoming Go 1.14.5 and Go 1.13.13 security releases

They have been pre-announced¹.

Also update the release summary template to not point to the issue
tracker for future releases. The issue tracker is representative of
the final release content only for releases that have been completed.

¹ https://groups.google.com/d/msg/golang-announce/f2c5bqrGH_g/GnH6k56AAAAJ

Change-Id: I1b05a0d6ce3f3f05a441979f529d449a2f49465e
Reviewed-on: https://go-review.googlesource.com/c/website/+/242317
Run-TryBot: Dmitri Shuralyov <dmitshur@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Katie Hockman <katie@golang.org>

cmd/golangorg/release.go

@@ -178,9 +178,11 @@ var releaseSummaryHTML = template.Must(template.New("").Parse(`
 	{{with .ComponentsAndPackages}} to {{.}}{{end}}.
 	{{.More}}
 
+	{{if .Released}}
 	See the
 	<a href="https://github.com/golang/go/issues?q=milestone%3AGo{{.V}}+label%3ACherryPickApproved">Go
 	{{.V}} milestone</a> on our issue tracker for details.
+	{{end}}
 {{else}}
 	{{.CustomSummary}}
 {{end}}

internal/history/release.go

@@ -31,6 +31,17 @@ type Release struct {
 // It contains entries for releases of Go 1.9 and newer.
 // Older releases are listed in doc/devel/release.html.
 var Releases = map[GoVer]Release{
+	{1, 14, 5}: {
+		Date:     Date{2020, 7, 14},
+		Security: true,
+		Future:   true,
+	},
+	{1, 13, 13}: {
+		Date:     Date{2020, 7, 14},
+		Security: true,
+		Future:   true,
+	},
+
 	{1, 14, 4}: {
 		Date: Date{2020, 6, 1},