[llvm] [bazel] update .bazelversion to 8.0.0 (PR #119425)

[Nick Desaulniers via llvm-commits]

nickdesaulniers wrote:

```diff
diff --git a/utils/bazel/WORKSPACE b/utils/bazel/WORKSPACE
index 66ba1ac1b17e..a3b8be7814d4 100644
--- a/utils/bazel/WORKSPACE
+++ b/utils/bazel/WORKSPACE
@@ -4,6 +4,7 @@
 
 load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
 load("@bazel_tools//tools/build_defs/repo:utils.bzl", "maybe")
+load("@rules_cc//cc:defs.bzl", "http_archive")
 
 SKYLIB_VERSION = "1.3.0"
 

```
didn't seem to work

https://github.com/llvm/llvm-project/pull/119425