Roll version to exercise release again

Author: Wilfred

Cargo.lock

@@ -4,7 +4,7 @@ description = "A diff that understands syntax"
 repository = "https://github.com/wilfred/difftastic"
 homepage = "http://difftastic.wilfred.me.uk/"
 license = "MIT"
-version = "0.26.2"
+version = "0.26.3"
 authors = ["Wilfred Hughes <[email protected]>"]
 keywords = ["diff", "syntax"]
 categories = ["development-tools", "command-line-utilities", "parser-implementations"]