cmd/golangorg, internal/history: update for Go 1.24.0 release

Start using the GOROOT content from release-branch.go1.24, and add an
entry for the Go 1.24.0 release to the release history.
Removing the draft notice from the release notes is done in CL 647797.

For golang/go#68545.

Change-Id: Ib30082d4dcc0afaadcf22ba07e5e5f7e3f4761bc
Reviewed-on: https://go-review.googlesource.com/c/website/+/648498
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
Auto-Submit: Dmitri Shuralyov <dmitshur@golang.org>

Author: dmitshur

cmd/golangorg/cloudbuild.yaml

@@ -5,7 +5,7 @@
 steps:
   # Clone go repo to _goroot.zip for use by uploaded app.
   - name: gcr.io/cloud-builders/git
-    args: ["clone", "--branch=release-branch.go1.23", "--depth=1", "https://go.googlesource.com/go", "_gotmp"]
+    args: ["clone", "--branch=release-branch.go1.24", "--depth=1", "https://go.googlesource.com/go", "_gotmp"]
   - name: gcr.io/cloud-builders/git
     args: ["archive", "--format=zip", "--output=../_goroot.zip", "HEAD"]
     dir: _gotmp

internal/history/release.go

@@ -13,6 +13,9 @@ import "html/template"
 //
 // The table is sorted by date, breaking ties with newer versions first.
 var Releases = []*Release{
+	{
+		Date: Date{2025, 2, 11}, Version: Version{1, 24, 0},
+	},
 	{
 		Date: Date{2025, 2, 4}, Version: Version{1, 23, 6},
 		Security: &FixSummary{