Bump signature from 1.3.0 to 1.3.1

Bumps [signature](https://github.com/RustCrypto/traits) from 1.3.0 to 1.3.1.
- [Release notes](https://github.com/RustCrypto/traits/releases)
- [Commits](https://github.com/RustCrypto/traits/compare/signature-v1.3.0...signature-v1.3.1)

---
updated-dependencies:
- dependency-name: signature
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

Cargo.lock

@@ -920,9 +920,9 @@ dependencies = [
 
 [[package]]
 name = "signature"
-version = "1.3.0"
+version = "1.3.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0f0242b8e50dd9accdd56170e94ca1ebd223b098eb9c83539a6e367d0f36ae68"
+checksum = "c19772be3c4dd2ceaacf03cb41d5885f2a02c4d8804884918e3a258480803335"
 
 [[package]]
 name = "simplelog"

Cargo.toml

@@ -21,7 +21,7 @@ ed25519-dalek = "1.0.1"
 x25519-dalek = "1.1.1"
 ecies-ed25519 = "0.5.1"
 chacha20poly1305 = "0.8.0"
-signature = "1.3.0"
+signature = "1.3.1"
 blakeout = "0.3.0"
 num_cpus = "1.13.0"
 byteorder = "1.4.3"