Add xfail to GRDB.swift

...due to https://bugs.swift.org/browse/SR-9151

Author: Clack Cole

projects.json

@@ -742,6 +742,15 @@
       {
         "action": "BuildSwiftPackage",
         "configuration": "release",
+        "xfail": {
+          "compatibility": {
+            "4.2": {
+              "branch": {
+                "master": "https://bugs.swift.org/browse/SR-9151"
+              }
+            }
+          }
+        },
         "tags": "sourcekit"
       },
       {