chore: be explicit that we require bazel 6.5.0 (#1160)

Attempting to use this repo with bazel 6.4.1 results in:

```
ERROR: https://bcr.bazel.build/modules/rules_jvm_external/6.1/MODULE.bazel:89:13: name 'use_repo_rule' is not defined
ERROR: Error computing the main repository mapping: in module dependency chain <root> -> [email protected] -> [email protected] -> [email protected]: error executing MODULE.bazel file for [email protected]
```

Document the minimum requirement of bazel 6.5.0. This is already
configured in the CI matrix.

Author: peakschris

MODULE.bazel

@@ -2,7 +2,7 @@
 
 module(
     name = "aspect_bazel_lib",
-    bazel_compatibility = [">=6.0.0"],
+    bazel_compatibility = [">=6.5.0"],
     compatibility_level = 1,
 )