go.mod: bump go version to 1.22

Change-Id: I908277e386116b893ddfaffec7de3b9ddc7ca441
Reviewed-on: https://review.monogon.dev/c/monogon/+/2982
Reviewed-by: Lorenz Brun <lorenz@monogon.tech>
Tested-by: Jenkins CI
diff --git a/go.mod b/go.mod
index 4d7bed3..268e87b 100644
--- a/go.mod
+++ b/go.mod
@@ -1,6 +1,6 @@
 module source.monogon.dev
 
-go 1.21
+go 1.22
 
 // Kubernetes is not fully consumable as a module, fix that
 replace (