config: regenerate upload config

This is an automated CL which updates the generated upload config.

[git-generate]
go generate ./internal/configgen

Change-Id: I2de413976dd2afa1fd9bcf6a26348e5824e2136e
Reviewed-on: https://go-review.googlesource.com/c/telemetry/+/730700
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Auto-Submit: Gopher Robot <gobot@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Reviewed-by: Madeline Kalil <mkalil@google.com>

config/config.json

diff --git a/config/config.json b/config/config.json
index c6c07d3..d6ac8e1 100644
--- a/config/config.json
+++ b/config/config.json
@@ -381,7 +381,8 @@
 		"go1.25.2",
 		"go1.25.3",
 		"go1.25.4",
-		"go1.25.5"
+		"go1.25.5",
+		"go1.26rc1"
 	],
 	"SampleRate": 1,
 	"Programs": [
@@ -426,7 +427,8 @@
 				"go1.25.2",
 				"go1.25.3",
 				"go1.25.4",
-				"go1.25.5"
+				"go1.25.5",
+				"go1.26rc1"
 			],
 			"Counters": [
 				{
@@ -483,7 +485,8 @@
 				"go1.25.2",
 				"go1.25.3",
 				"go1.25.4",
-				"go1.25.5"
+				"go1.25.5",
+				"go1.26rc1"
 			],
 			"Counters": [
 				{