Fix EOL related build issues on Windows

[madmini]

Proper fix for #1275 that does no longer require manual intervention.

On Windows, git has core.autocrlf=true set at system level, hence any Windows user who has not changed their global git config will checkout all text files with CRLF line endings. For some files this seems to cause build issues.

With this change, I can build using docker on Windows 11 as follows:

git clone https://github.com/madmini/InfiniTime.git --branch fix/eol-on-windows
cd InfiniTime
git submodule update --init
docker run --rm -it -v ${PWD}:/sources infinitime/infinitime-build

Without the change, the build fails with an error that matches the one described in #1275:

...
[ 34%] Linking C static library libnimble.a
[ 34%] Built target nimble
gmake: *** [Makefile:91: all] Error 2

---

Note: when changing between branches with varying .gitattributes with checkout instead of directly cloning with --branch, resetting the line endings is more complicated:

git clone https://github.com/madmini/InfiniTime.git
# CRLF line endings
git checkout fix/eol-on-windows
# still CRLF line endings
git rm --cached -r .
git reset --hard
# LF line endings

[github-actions]

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[NeroBurner]

looking good. No change in behavior on supported platforms (i.e. Linux) and possible fix for Windows builds. Just suggesting a few comments for future "us" to know why we don't have native line endings

[NeroBurner]

looking good. I'm scheduling for 1.16.0 as 1.15.0 feels close