Make tests pass on Windows

[JohnGurin]

When there is no git global setting for aoutocrlf, git checkouts files with EOLs accordingly to the platform.
On Windows with CRLF tests become broken.

Using platform's EOLs does not completely help.

// src/components.ts
import { EOL } from 'node:os'
[...].join(/*'\n' -> */ EOL)

Snapshots have file size in them which differs because CRLF is two chars.

# Heading output for `bol-dot-com.css`
───────────────────────────────────────────────────────────
Lines of Code │ Filesize │ Rules │ Selectors │ Declarations
17,818        │ 468.9KB  │ 4,757 │ 6,664     │ 10,083  <-- size in file content
17,818        │ 469KB    │ 4,757 │ 6,664     │ 10,083  <-- actual file size (when CRLF)
───────────────────────────────────────────────────────────

Adding explicit line endings for the test files in .gitattributes makes tests pass on Windows.