[librsvg] Use cargo-features=["edition"] to be able to vendor with the 2018 edition

[Federico Mena Quintero <federico src gnome org>]

commit 6099469d7248aa6b2103c64417f9208049e97ec3
Author: Federico Mena Quintero <federico gnome org>
Date:   Mon May 13 17:53:45 2019 -0500

    Use cargo-features=["edition"] to be able to vendor with the 2018 edition

 Cargo.lock                | 2 --
 librsvg_crate/Cargo.toml  | 3 +++
 rsvg_internals/Cargo.toml | 2 ++
 3 files changed, 5 insertions(+), 2 deletions(-)
---
diff --git a/Cargo.lock b/Cargo.lock
index 2501e0ef..a33aca00 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1,5 +1,3 @@
-# This file is automatically @generated by Cargo.
-# It is not intended for manual editing.
 [[package]]
 name = "aho-corasick"
 version = "0.6.10"
diff --git a/librsvg_crate/Cargo.toml b/librsvg_crate/Cargo.toml
index 294c63fe..5cf5fc1f 100644
--- a/librsvg_crate/Cargo.toml
+++ b/librsvg_crate/Cargo.toml
@@ -1,3 +1,5 @@
+cargo-features = ["edition"]
+
 [package]
 name = "librsvg"
 version = "0.0.1"
@@ -22,3 +24,4 @@ rsvg_internals = { path = "../rsvg_internals" }
 
 [build-dependencies]
 pkg-config = "0.3.14"
+
diff --git a/rsvg_internals/Cargo.toml b/rsvg_internals/Cargo.toml
index bfa2bd16..787b2842 100644
--- a/rsvg_internals/Cargo.toml
+++ b/rsvg_internals/Cargo.toml
@@ -1,3 +1,5 @@
+cargo-features = ["edition"]
+
 [package]
 name = "rsvg_internals"
 version = "0.0.1"