Bump to rules_go 0.39.1 for Bazel 7 compatibility

`bazel run //tools:lint_{check,fix}` required updating rules_go to
0.39.1 to work under Bazel 7.

The previous rules_go version 0.38.1 caused the following error:

```txt
$ ./test_lint.sh
ERROR: .../external/io_bazel_rules_go/BUILD.bazel:71:16:
  in (an implicit dependency) attribute of go_context_data rule
  @@io_bazel_rules_go//:go_context_data:
  in $whitelist_function_transition attribute of go_context_data rule
  @@io_bazel_rules_go//:go_context_data: package group
  '@@bazel_tools//tools/whitelists/function_transition_whitelist:function_transition_whitelist'
  is misplaced here (they are only allowed in the visibility attribute)

ERROR: .../external/io_bazel_rules_go/BUILD.bazel:71:16:
  Analysis of target '@@io_bazel_rules_go//:go_context_data' failed

ERROR: Analysis of target '//tools:lint_check' failed;
  build aborted: Analysis failed
```

Author: mbland

WORKSPACE

@@ -138,10 +138,10 @@ format_repositories()
 
 http_archive(
     name = "io_bazel_rules_go",
-    sha256 = "dd926a88a564a9246713a9c00b35315f54cbd46b31a26d5d8fb264c07045f05d",
+    sha256 = "6dc2da7ab4cf5d7bfc7c949776b1b7c733f05e56edc4bcd9022bb249d2e2a996",
     urls = [
-        "https://mirror.bazel.build/github.com/bazelbuild/rules_go/releases/download/v0.38.1/rules_go-v0.38.1.zip",
-        "https://github.com/bazelbuild/rules_go/releases/download/v0.38.1/rules_go-v0.38.1.zip",
+        "https://mirror.bazel.build/github.com/bazelbuild/rules_go/releases/download/v0.39.1/rules_go-v0.39.1.zip",
+        "https://github.com/bazelbuild/rules_go/releases/download/v0.39.1/rules_go-v0.39.1.zip",
     ],
 )