Bump to comrak 0.7

Author: jtgeibel

Cargo.lock

@@ -52,7 +52,7 @@ swirl = { git = "https://github.com/sgrif/swirl.git", rev = "e87cf37" }
 serde_json = "1.0.0"
 serde = { version = "1.0.0", features = ["derive"] }
 chrono = { version = "0.4.0", features = ["serde"] }
-comrak = { version = "0.4.0", default-features = false }
+comrak = { version = "0.7", default-features = false }
 ammonia = "3.0.0"
 docopt = "1.0"
 scheduled-thread-pool = "0.2.0"