use UNIX-style line endings
minor #546 Set UNIX line ending in .editorconfig (bgotink)

This PR was merged into the 1.0.x-dev branch.

Discussion
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Set UNIX line ending in .editorconfig

This PR changes the line ending requested in .editorconfig to the linefeed character, as required by PSR-2.

Commits
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63d6573 use UNIX-style line endings