internal/history: document Go 1.16.2 and Go 1.15.10

Updates golang/go#44943
Updates golang/go#44944

Change-Id: Ic8391e46d039ece835791ad0a13a5ccfa41ff7e5
Reviewed-on: https://go-review.googlesource.com/c/website/+/301009
Trust: Carlos Amedee <carlos@golang.org>
Run-TryBot: Carlos Amedee <carlos@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Jeremy Faller <jeremy@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
diff --git a/internal/history/release.go b/internal/history/release.go
index e67f6b4..1d6965e 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, 16, 2}: {
+		Date: Date{2021, 3, 11},
+
+		Components: []template.HTML{"cgo", "the compiler", "linker", "the <code>go</code> command"},
+		Packages:   []string{"syscall", "time"},
+	},
+	{1, 15, 10}: {
+		Date: Date{2021, 3, 11},
+
+		Components: []template.HTML{"the compiler", "the <code>go</code> command"},
+		Packages:   []string{"net/http", "os", "syscall", "time"},
+	},
+
 	{1, 16, 1}: {
 		Date:     Date{2021, 3, 10},
 		Security: true,