Improve naming of a method

Since we have `ignore` settings, this may lead code reader into thinking
we actually support skipping lockfiles through `dependabot.yml`. This is
just trying to respect a package manager specific setting, so let's
rename it to reduce confusion.

npm_and_yarn/lib/dependabot/npm_and_yarn/file_fetcher.rb

@@ -173,7 +173,7 @@ def package_json
       def package_lock
         return @package_lock if defined?(@package_lock)
 
-        @package_lock = fetch_file_if_present("package-lock.json") unless ignore_package_lock?
+        @package_lock = fetch_file_if_present("package-lock.json") unless skip_package_lock?
       end
 
       def yarn_lock
@@ -490,7 +490,7 @@ def parsed_shrinkwrap
         {}
       end
 
-      def ignore_package_lock?
+      def skip_package_lock?
         return false unless npmrc
 
         npmrc.content.match?(/^package-lock\s*=\s*false/)