fixed check to determine if we are in wsl2

vafschoen · vafschoen · commit 4b0822e3687f · 2020-10-15T12:10:40.000+02:00
diff --git a/lib/vagrant-hostmanager/hosts_file/updater.rb b/lib/vagrant-hostmanager/hosts_file/updater.rb
@@ -208,7 +208,7 @@ def self.windows?
           end
 
           def self.wsl?
-            defined?(ENV['WSLENV'])
+            ENV.include?('WSLENV')
           end
 
           require 'win32ole' if windows?
