internal/history: document Go 1.15.4 and Go 1.14.11

Updates golang/go#42403
Updates golang/go#42404

Change-Id: I3e3809562596945c2e1fab9f61191d01db68120f
Reviewed-on: https://go-review.googlesource.com/c/website/+/267897
Trust: Alexander Rakoczy <alex@golang.org>
Run-TryBot: Alexander Rakoczy <alex@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Carlos Amedee <carlos@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
diff --git a/internal/history/release.go b/internal/history/release.go
index 27e2e09..08ce0a6 100644
--- a/internal/history/release.go
+++ b/internal/history/release.go
@@ -31,6 +31,19 @@
 // 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, 15, 4}: {
+		Date: Date{2020, 11, 5},
+
+		Components: []template.HTML{"cgo", "the compiler", "linker", "runtime"},
+		Packages:   []string{"compress/flate", "net/http", "reflect", "time"},
+	},
+	{1, 14, 11}: {
+		Date: Date{2020, 11, 5},
+
+		Components: []template.HTML{"the runtime"},
+		Packages:   []string{"net/http", "time"},
+	},
+
 	{1, 15, 3}: {
 		Date: Date{2020, 10, 14},