ignore/types: add lock files

Treat anything with a `.lock` extension as a lock file, with
an extra rule or two for special cases, e.g., package-lock.json.

ignore/src/types.rs

@@ -196,6 +196,7 @@ const DEFAULT_TYPES: &'static [(&'static str, &'static [&'static str])] = &[
         "OFL-*[0-9]*",
     ]),
     ("lisp", &["*.el", "*.jl", "*.lisp", "*.lsp", "*.sc", "*.scm"]),
+    ("lock", &["*.lock", "package-lock.json"]),
     ("log", &["*.log"]),
     ("lua", &["*.lua"]),
     ("lzma", &["*.lzma"]),