Relax version requirements of dependencies

Author: kngwyu

Cargo.toml

@@ -19,20 +19,20 @@ travis-ci = { repository = "PyO3/pyo3", branch = "master" }
 appveyor = { repository = "fafhrd91/pyo3" }
 
 [dependencies]
-indoc = "0.3.4"
-inventory = "0.1.4"
-libc = "0.2.62"
-num-bigint = { version = ">= 0.2", optional = true }
-num-complex = { version = ">= 0.2", optional = true }
-num-traits = "0.2.8"
+indoc = "^0.3.4"
+inventory = "^0.1.4"
+libc = "^0.2.62"
+num-bigint = { version = "0.2", optional = true }
+num-complex = { version = "0.2", optional = true }
+num-traits = "^0.2.8"
 parking_lot = { version = "0.10", features = ["nightly"] }
-paste = "0.1.6"
+paste = "^0.1.6"
 pyo3cls = { path = "pyo3cls", version = "=0.9.0-alpha.1" }
-unindent = "0.1.4"
+unindent = "^0.1.4"
 
 [dev-dependencies]
 assert_approx_eq = "1.1.0"
-trybuild = "1.0.14"
+trybuild = "1.0.23"
 
 [build-dependencies]
 regex = "1"