Bump dependency versions

spearman · spearman · commit 94dca31d04be · 2018-05-08T22:12:06.000-07:00
diff --git a/Cargo.toml b/Cargo.toml
@@ -13,9 +13,9 @@ readme = "README.md"
 
 [dependencies]
 num-traits = "0.2"
-proc-macro2 = "0.2.1"
-quote = "0.4.2"
-syn = "0.12.7"
+proc-macro2 = "0.3.8"
+quote = "0.5.2"
+syn = "0.13.7"
 
 [dev-dependencies]
 num = "0.1"
