diff --git a/Cargo.lock b/Cargo.lock
index f9834aa1..b71c38eb 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -106,7 +106,7 @@ dependencies = [
  "colored 1.6.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "env_logger 0.5.11 (registry+https://github.com/rust-lang/crates.io-index)",
  "failure 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "petgraph 0.4.12 (registry+https://github.com/rust-lang/crates.io-index)",
+ "petgraph 0.4.13 (registry+https://github.com/rust-lang/crates.io-index)",
  "structopt 0.2.10 (registry+https://github.com/rust-lang/crates.io-index)",
  "syn 0.14.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "walkdir 2.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -614,7 +614,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "petgraph"
-version = "0.4.12"
+version = "0.4.13"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "fixedbitset 0.1.9 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1155,7 +1155,7 @@ dependencies = [
 "checksum openssl-sys 0.9.33 (registry+https://github.com/rust-lang/crates.io-index)" = "d8abc04833dcedef24221a91852931df2f63e3369ae003134e70aff3645775cc"
 "checksum ordermap 0.3.5 (registry+https://github.com/rust-lang/crates.io-index)" = "a86ed3f5f244b372d6b1a00b72ef7f8876d0bc6a78a4c9985c53614041512063"
 "checksum percent-encoding 1.0.1 (registry+https://github.com/rust-lang/crates.io-index)" = "31010dd2e1ac33d5b46a5b413495239882813e0369f8ed8a5e266f173602f831"
-"checksum petgraph 0.4.12 (registry+https://github.com/rust-lang/crates.io-index)" = "8b30dc85588cd02b9b76f5e386535db546d21dc68506cff2abebee0b6445e8e4"
+"checksum petgraph 0.4.13 (registry+https://github.com/rust-lang/crates.io-index)" = "9c3659d1ee90221741f65dd128d9998311b0e40c5d3c23a62445938214abce4f"
 "checksum pkg-config 0.3.12 (registry+https://github.com/rust-lang/crates.io-index)" = "6a52e4dbc8354505ee07e484ab07127e06d87ca6fa7f0a516a2b294e5ad5ad16"
 "checksum proc-macro2 0.4.9 (registry+https://github.com/rust-lang/crates.io-index)" = "cccdc7557a98fe98453030f077df7f3a042052fae465bb61d2c2c41435cfd9b6"
 "checksum quick-error 1.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "9274b940887ce9addde99c4eee6b5c44cc494b182b97e73dc8ffdcb3397fd3f0"
diff --git a/Cargo.toml b/Cargo.toml
index 8179d689..c0fa9097 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -18,7 +18,7 @@ clap = "2.32.0"
 cargo = "0.28.0"
 env_logger = "0.5.11"
 failure = "0.1.1"
-petgraph = "0.4.12"
+petgraph = "0.4.13"
 structopt = "0.2.10"
 walkdir = "2.1.4"
 colored = "1.6.1"