Revert to use published version of tree_magic_mini.
https://github.com/Wilfred/difftastic/commit/b662a2220b9e9eae5f69ecbc31195bcfcc5216e1
Index: Cargo.lock
--- Cargo.lock.orig
+++ Cargo.lock
@@ -862,8 +862,9 @@ dependencies = [
 
 [[package]]
 name = "tree_magic_mini"
-version = "3.0.2"
-source = "git+https://github.com/Wilfred/tree_magic?branch=fix-panic-for-empty-strings#13dd6dda15c7062bd8f7dd5bc9bb5b16ce9ee613"
+version = "3.0.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "91adfd0607cacf6e4babdb870e9bec4037c1c4b151cfd279ccefc5e0c7feaa6d"
 dependencies = [
  "bytecount",
  "fnv",