Use .gitattributes to normalise line endings on check-in

Remove the mixed line endings pre-commit hook because it is obsolete.

Relying on git to handle line endings means contributors have more
flexibility with which line endings they want to use on check-out.
The settings in .gitattributes only impose which line endings will
be used upon check-in (LF), which should not impact local development;
git will still respect the core.eol and core.autocrlf settings.

Author: MarkKoz

.gitattributes

@@ -0,0 +1 @@
+* text=auto

.pre-commit-config.yaml

@@ -7,8 +7,6 @@ repos:
       - id: check-yaml
         args: [--unsafe] # Required due to custom constructors (e.g. !ENV)
       - id: end-of-file-fixer
-      - id: mixed-line-ending
-        args: [--fix=lf]
       - id: trailing-whitespace
         args: [--markdown-linebreak-ext=md]
   - repo: https://github.com/pre-commit/pygrep-hooks