Proj4051: Use equals sign for key-value assignments

An EditorConfig file helps maintain consistent coding styles for multiple developers working on the same project across various editors and IDEs.

The specification states that = should be used as assignment character, not :. Multiple IDEs (including Visual Studio), however, do support the :.

Non-compliant

[*]
end_of_line: crlf

Compliant

[*]
end_of_line = crlf