Set RULES_GO_VERSION to 0.26.0 (#2838)

diff --git a/go/def.bzl b/go/def.bzl
index 232e087..51668de 100644
--- a/go/def.bzl
+++ b/go/def.bzl
@@ -116,7 +116,7 @@
 
 # Current version or next version to be tagged. Gazelle and other tools may
 # check this to determine compatibility.
-RULES_GO_VERSION = "0.25.0"
+RULES_GO_VERSION = "0.26.0"
 
 declare_toolchains = _declare_toolchains
 go_context = _go_context