chore: upgrade to go 1.26 (#228)

Updates go.mod and GitHub Actions workflow to use Go 1.26.

Relates to: open-cluster-management-io/ocm#1555

Signed-off-by: Tesshu Flower <tflower@redhat.com>

Author: tesshuflower

.github/workflows/go.yml

@@ -13,7 +13,7 @@ on:
 
 env:
   # Common versions
-  GO_VERSION: '1.25'
+  GO_VERSION: '1.26'
   GO_REQUIRED_MIN_VERSION: ''
 defaults:
   run:

go.mod

@@ -1,6 +1,6 @@
 module open-cluster-management.io/sdk-go
 
-go 1.25.0
+go 1.26.0
 
 require (
 	cloud.google.com/go/pubsub/v2 v2.3.0