Use only lower-case directory names

[joostmeijles]

Although the Windows filesystem is not case-sensitive, some Docker commands are. For example COPY /files/*.pfx /Files/ (which uses file look-up & expansion) is case-sensitive.

To prevent these issues, it will be better to only use lower-case directory names iso the currently mixed approached.

[lsubi]

This issue came up for me. I initially created the /Files folder in the root of sitecore-docker folder. When the build failed during the COPY command mentioned, renaming my "Files" folder to "files" fixed it. Might be helpful to indicate clearly in the README.md that you have to create a /files folder before building.

Thanks to all for contributing to this repo!

[joostmeijles]

Directory is now named files in README.md.