Bump dependency on meta to 1.1.8, which includes @nonvirtual (#2258)

Author: srawlins

pubspec.yaml

@@ -19,7 +19,7 @@ dependencies:
   logging: ^0.11.3+1
   process: ^3.0.5
   markdown: ^2.1.1
-  meta: ^1.0.0
+  meta: ^1.1.8
   mustache: ^1.1.0
   package_config: '>=0.1.5 <2.0.0'
   path: ^1.3.0