Explicitly enable ERB linters

I thought SelfClosingTag was enabled since it was on the list and the
`enabled: false` got lost among all the `enabled: true`. ERB Lint 0.1
and later will also add RequireInputAutocomplete as a default linter,
and we're not interested in it, at least for now.

So, just like we do for Rubocop, we're disabling all linters and
enabling the ones we use explicitly.

.erb-lint.yml

@@ -1,5 +1,8 @@
 ---
+EnableDefaultLinters: false
 linters:
+  AllowedScriptType:
+    enabled: true
   ClosingErbTagIndent:
     enabled: true
   ErbSafety:
@@ -10,8 +13,10 @@ linters:
     enabled: true
   NoJavascriptTagHelper:
     enabled: true
-  SelfClosingTag:
-    enabled: false
+  ParserErrors:
+    enabled: true
+  RightTrim:
+    enabled: true
   SpaceAroundErbTag:
     enabled: true
   SpaceIndentation: