chore: force patches to be checked out with LF line endings

[nornagon]

If a user has core.autoclrf set to true in their git config, on Windows, git
will check out .patch files with CRLF line endings, which git apply doesn't
understand (& thus gclient sync will fail with a message about being unable
to apply patches). This forces git to always check out *.patch files with LF
line endings, regardless of the core.autoclrf setting.

Ref #14662, and thanks to @vulture for the suggestion.

• PR description included and stakeholders cc'd
• PR title follows semantic commit guidelines

Notes: no-notes

[jkleinsc]

LGTM

[jkleinsc]

LGTM

[release-clerk]

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