Always set go.sum/go.mod line endings as LF (thrasher-corp#391)

thrasher- · web-flow · commit 49b9eced66b7 · 2019-12-03T13:33:28.000+11:00
Saves having Windows users experience pain and suffering as documented here: golang/go#31870
diff --git a/.gitattributes b/.gitattributes
@@ -0,0 +1,2 @@
+go.mod text eol=lf
+go.sum text eol=lf
