Constrain only the two important dependencies

serde_macros/Cargo.toml

@@ -25,8 +25,8 @@ clippy = "^0.*"
 compiletest_rs = "^0.2.0"
 fnv = "1.0"
 rustc-serialize = "^0.3.16"
-serde = "=0.8.0"
-serde_test = "=0.8.0"
+serde = "0.8.0"
+serde_test = "0.8.0"
 
 [[test]]
 name = "test"

serde_test/Cargo.toml

@@ -11,4 +11,4 @@ keywords = ["serde", "serialization"]
 include = ["Cargo.toml", "src/**/*.rs"]
 
 [dependencies]
-serde = "=0.8.0"
+serde = "0.8.0"