Update the nitrokey-sys version specification to ~3.4

Previously, we required nitrokey-sys version 3.4, which allows the
upgrade to nitrokey-sys 3.5.  Unfortunately, libnitrokey version 3.5,
which is packaged as nitrokey-sys 3.5, introduced breaking changes,
breaking the semantic versioning guarantees and causing compilation
errors if this version is selected.

This patch changes the version specification from 3.4 to ~3.4, i. e. >=
3.4.0, < 3.5.0, to make sure that nitrokey-rs can be compiled without
errors.

2 files changed, 4 insertions, 1 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index edc33f6..61cdf13 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,6 @@
+# Unreleased
+- Update the nitrokey-sys dependency version specification to ~3.4.
+
 # v0.3.4 (2019-01-20)
 - Fix authentication methods that assumed that `char` is signed.
 
diff --git a/Cargo.toml b/Cargo.toml
index 838ab45..2db9326 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -18,7 +18,7 @@ test-storage = []
 
 [dependencies]
 libc = "0.2"
-nitrokey-sys = "3.4"
+nitrokey-sys = "~3.4"
 rand_core = {version = "0.3", default-features = false}
 rand_os = {version = "0.1"}