internal/history: document Go 1.20.7 and 1.19.12 releases

For both minor releases, backported CLs were:

crypto/tls: restrict RSA keys in certificates to <= 8192 bits
cmd/asm, cmd/internal/obj: generate proper atomic ops for riscv64
net: tolerate permission errors in interface tests
cmd/compile: on PPC64, fix sign/zero extension when masking

Change-Id: I0f13a6a6251b50f8576ca522c7714ddf3975afc7
Reviewed-on: https://go-review.googlesource.com/c/website/+/514996
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: David Chase <drchase@google.com>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>

internal/history/release.go

@@ -14,6 +14,22 @@ import "html/template"
 //
 // The table is sorted by date, breaking ties with newer versions first.
 var Releases = []*Release{
+	{
+		Date: Date{2023, 8, 1}, Version: Version{1, 20, 7},
+		Security: &FixSummary{Quantifier: "a", Packages: []string{"crypto/tls"}},
+		Bug: &FixSummary{
+			Components: []template.HTML{"the assembler", "the compiler"},
+			Packages:   []string{},
+		},
+	},
+	{
+		Date: Date{2023, 8, 1}, Version: Version{1, 19, 12},
+		Security: &FixSummary{Quantifier: "a", Packages: []string{"crypto/tls"}},
+		Bug: &FixSummary{
+			Components: []template.HTML{"the assembler", "the compiler"},
+			Packages:   []string{},
+		},
+	},
 	{
 		Date: Date{2023, 7, 11}, Version: Version{1, 20, 6},
 		Security: &FixSummary{Quantifier: "a", Packages: []string{"net/http"}},