Normalise Line endings (#1284)

* Add .gitattributes

* Normalise line endings

.gitattributes

+# 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.
+
+# Declare files that will always have LF line endings on checkout.
+*.yml text eol=lf
+
+# Declare files that will always have CRLF line endings on checkout.
+*.cs text eol=crlf
+
+# Denote all files that are truly binary and should not be modified.
+*.png binary
+*.jpg binary