upgrade go version (#947)

chaptersix · web-flow · commit 5019c64d0481 · 2026-02-19T11:36:45.000-06:00
## What was changed
bump to 1.26

## Why?
CVEs in standard lib
diff --git a/go.mod b/go.mod
@@ -1,6 +1,6 @@
 module github.com/temporalio/cli
 
-go 1.25.5
+go 1.26.0
 
 require (
 	github.com/BurntSushi/toml v1.4.0
