internal/history: document future Go 1.19.1 and 1.18.6 releases

Change-Id: I0b85c82c9f3c6f4ce3bca34ff55051dda9d682d2
Reviewed-on: https://go-review.googlesource.com/c/website/+/427334
TryBot-Result: Gopher Robot <gobot@golang.org>
Auto-Submit: Dmitri Shuralyov <dmitshur@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Run-TryBot: Dmitri Shuralyov <dmitshur@golang.org>
Reviewed-by: Damien Neil <dneil@google.com>

internal/history/release.go

@@ -14,6 +14,16 @@ import "golang.org/x/website/internal/backport/html/template"
 //
 // The table is sorted by date, breaking ties with newer versions first.
 var Releases = []*Release{
+	{
+		Date: Date{2022, 9, 6}, Version: Version{1, 19, 1},
+		Future:   true,
+		Security: &FixSummary{Components: []template.HTML{"the standard library"}},
+	},
+	{
+		Date: Date{2022, 9, 6}, Version: Version{1, 18, 6},
+		Future:   true,
+		Security: &FixSummary{Components: []template.HTML{"the standard library"}},
+	},
 	{
 		Date: Date{2022, 8, 2}, Version: Version{1, 19, 0},
 	},