Build with Go 1.26

Interestingly, I don't see any meaningful changes to make based on the
release notes. `go fix ./...` has no effect either.

Author: featherbread

go.mod

@@ -1,6 +1,6 @@
 module github.com/featherbread/randomizer
 
-go 1.25.0
+go 1.26.0
 
 require (
 	cloud.google.com/go/firestore v1.18.0