Set .go tab size to 4 in .editorconfig (#8099)

Tab size was added as 2 in .editorconfig but a tab size of 4 is used
throughout go code base.

This can cause editors such as vscode to automatically reformat open .go
files to tab size 2 from 4.

.editorconfig

@@ -3,7 +3,7 @@ root = true
 
 [*.go]
 indent_style = tab
-indent_size = 2
+indent_size = 4
 charset = utf-8
 trim_trailing_whitespace = true
 insert_final_newline = true