add .gitattributes file to enforce lf line-endings

.gitattributes

@@ -0,0 +1,7 @@
+# We'll let Git's auto-detection algorithm infer if a file is text. If it is,
+# enforce LF line endings regardless of OS or git configurations.
+* text=auto eol=lf
+
+# Isolate binary files in case the auto-detection algorithm fails and
+# marks them as text files (which could brick them).
+*.{png,jpg,jpeg,gif,webp,woff,woff2} binary