Declare rules_swift max_compatibility_version = 2, set rules_swift to 1.18.0 (#2725)

Author: erikkerber

MODULE.bazel

@@ -6,4 +6,4 @@ module(
 
 bazel_dep(name = "apple_support", version = "1.13.0", repo_name = "build_bazel_apple_support")
 bazel_dep(name = "rules_apple", version = "3.3.0", repo_name = "build_bazel_rules_apple")
-bazel_dep(name = "rules_swift", version = "1.16.0", repo_name = "build_bazel_rules_swift")
+bazel_dep(name = "rules_swift", version = "1.18.0", max_compatibility_level = 2, repo_name = "build_bazel_rules_swift")