style: normalize line ending to LF

.gitattributes

@@ -0,0 +1,19 @@
+# Set the default behavior, in case people don't have core.autocrlf set.
+* text=auto
+
+
+# Explicitly declare text files you want to always be normalized and converted
+# to native line endings on checkout.
+*.tsv text
+*.yml text
+*.xml text
+*.md text
+*.txt text
+*.json text
+*.rst text
+
+
+# Denote all files that are truly binary and should not be modified.
+*.xlsx
+*.docx
+*.mat