internal/dl: update macOS requirement to 12

Per https://go.dev/doc/go1.25#darwin.

For golang/go#69839.

Change-Id: I66ba4c7cd688a743762e31a33a5d9eba3e9bfc5b
Reviewed-on: https://go-review.googlesource.com/c/website/+/681136
LUCI-TryBot-Result: Go LUCI <[email protected]>
Reviewed-by: Cherry Mui <[email protected]>
Auto-Submit: Dmitri Shuralyov <[email protected]>
Reviewed-by: Dmitri Shuralyov <[email protected]>

Author: dmitshur

internal/dl/dl.go

@@ -165,12 +165,12 @@ var featuredFiles = []Feature{
 	},
 	{
 		Platform:     "Apple macOS (ARM64)",
-		Requirements: "macOS 11 or later, Apple 64-bit processor",
+		Requirements: "macOS 12 or later, Apple 64-bit processor",
 		fileRE:       regexp.MustCompile(`\.darwin-arm64\.pkg$`),
 	},
 	{
 		Platform:     "Apple macOS (x86-64)",
-		Requirements: "macOS 11 or later, Intel 64-bit processor",
+		Requirements: "macOS 12 or later, Intel 64-bit processor",
 		fileRE:       regexp.MustCompile(`\.darwin-amd64\.pkg$`),
 	},
 	{