Add max_compatibility_level = 3 for rules_swift dep

The upcoming `rules_swift` release bumps `compatibility_level`
from 2 to 3. Without `max_compatibility_level = 3` on the
`bazel_dep`, Bzlmod rejects the resolution when downstream
projects use that release (or a git override at a commit past
the bump). Other modules in the ecosystem (`rules_apple`,
`rules_swift_package_manager`, `swift-syntax`,
`swift-index-store`) already declare this.

Author: jpsim

MODULE.bazel

@@ -17,6 +17,7 @@ bazel_dep(name = "rules_cc", version = "0.2.17")
 bazel_dep(
     name = "rules_swift",
     version = "3.5.0",
+    max_compatibility_level = 3,
     repo_name = "build_bazel_rules_swift",
 )
 bazel_dep(