Force package*.json to use LF

NPM and Lerna have inconsistent behavior around line endings
depending on the versions used. Forcing these files to be LF
on all platforms gets around these issues.

.editorconfig

@@ -9,3 +9,6 @@ trim_trailing_whitespace = true
 
 [*.{yml,json,bicep}]
 indent_size = 2
+
+[package*.json]
+end_of_line = lf

.gitattributes

@@ -1 +1,2 @@
 * text=auto
+package*.json text eol=lf