Update version_script to be handled as linkopt

This allows us to handle this consistently between cc_binary and
cc_library* types.

Test: build/bazel/ci/bp2build.sh
Change-Id: I996f42bbe591215217c3d561662e775925b871ff

bp2build/cc_library_shared_conversion_test.go

@@ -361,7 +361,8 @@ cc_library_shared {
 }`,
 		expectedBazelTargets: []string{`cc_library_shared(
     name = "foo_shared",
-    version_script = "version_script",
+    additional_linker_inputs = ["version_script"],
+    linkopts = ["-Wl,--version-script,$(location version_script)"],
 )`},
 	})
 }