internal/history: document Go 1.21.4 and 1.20.11 releases

Change-Id: Id5deb52b58464da68bb47599c1ed82a32944ddf6
Reviewed-on: https://go-review.googlesource.com/c/website/+/540298
Reviewed-by: Cherry Mui <cherryyz@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
diff --git a/internal/history/release.go b/internal/history/release.go
index 62a7cdc..7eb0eac 100644
--- a/internal/history/release.go
+++ b/internal/history/release.go
@@ -15,6 +15,22 @@
 // The table is sorted by date, breaking ties with newer versions first.
 var Releases = []*Release{
 	{
+		Date: Date{2023, 11, 7}, Version: Version{1, 21, 4},
+		Security: &FixSummary{Packages: []string{"path/filepath"}},
+		Bug: &FixSummary{
+			Components: []template.HTML{"the linker", "the runtime", "the compiler"},
+			Packages:   []string{"go/types", "net/http", "runtime/cgo"},
+		},
+	},
+	{
+		Date: Date{2023, 11, 7}, Version: Version{1, 20, 11},
+		Security: &FixSummary{Packages: []string{"path/filepath"}},
+		Bug: &FixSummary{
+			Components: []template.HTML{"the linker"},
+			Packages:   []string{"net/http"},
+		},
+	},
+	{
 		Date: Date{2023, 10, 10}, Version: Version{1, 21, 3},
 		Security: &FixSummary{Quantifier: "a", Packages: []string{"net/http"}},
 	},