diff --git a/Cargo.lock b/Cargo.lock
index af787b3e..5800a7b5 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -531,6 +531,12 @@ dependencies = [
  "unicode-segmentation",
 ]
 
+[[package]]
+name = "heck"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2540771e65fc8cb83cd6e8a237f70c319bd5c29f78ed1084ba5d50eeac86f7f9"
+
 [[package]]
 name = "hermit-abi"
 version = "0.1.19"
@@ -1528,9 +1534,9 @@ checksum = "9def91fd1e018fe007022791f865d0ccc9b3a0d5001e01aabb8b40e46000afb5"
 
 [[package]]
 name = "snafu"
-version = "0.7.0"
+version = "0.7.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "2eba135d2c579aa65364522eb78590cdf703176ef71ad4c32b00f58f7afb2df5"
+checksum = "cb0656e7e3ffb70f6c39b3c2a86332bb74aa3c679da781642590f3c1118c5045"
 dependencies = [
  "backtrace",
  "doc-comment",
@@ -1539,11 +1545,11 @@ dependencies = [
 
 [[package]]
 name = "snafu-derive"
-version = "0.7.0"
+version = "0.7.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7a7fe9b0669ef117c5cabc5549638528f36771f058ff977d7689deb517833a75"
+checksum = "475b3bbe5245c26f2d8a6f62d67c1f30eb9fffeccee721c45d162c3ebbdf81b2"
 dependencies = [
- "heck",
+ "heck 0.4.0",
  "proc-macro2",
  "quote",
  "syn",
@@ -1588,7 +1594,7 @@ version = "0.4.18"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "dcb5ae327f9cc13b68763b5749770cb9e048a99bd9dfdfa58d0cf05d5f64afe0"
 dependencies = [
- "heck",
+ "heck 0.3.3",
  "proc-macro-error",
  "proc-macro2",
  "quote",