adding a tweaks for string freezes

.rubocop.yml

@@ -1,5 +1,5 @@
 AllCops:
-  TargetRubyVersion: 2.7
+  TargetRubyVersion: 3.1
   Exclude:
     - "spec/data/**/*"
     - "vendor/**/*"

lib/ohai/loader.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 #
 # Author:: Claire McQuin (<claire@chef.io>)
 # Copyright:: Copyright (c) Chef Software Inc.
@@ -97,10 +98,10 @@ def load_plugin(plugin_path)
     # @return [Object] class object for the ohai plugin defined in the file
     def load_plugin_class(plugin_path)
       # Read the contents of the plugin to understand if it's a V6 or V7 plugin.
-      contents = ""
+      contents = nil
       begin
         logger.trace("Loading plugin at #{plugin_path}")
-        contents << File.read(plugin_path)
+        contents = File.read(plugin_path)
       rescue IOError, Errno::ENOENT
         logger.warn("Unable to open or read plugin at #{plugin_path}")
         return nil

lib/ohai/plugins/eucalyptus.rb

@@ -29,7 +29,7 @@
   provides "eucalyptus"
   depends "network/interfaces"
 
-  MAC_MATCH = /^[dD]0:0[dD]:/.freeze unless defined?(MAC_MATCH)
+  MAC_MATCH = /^[dD]0:0[dD]:/ unless defined?(MAC_MATCH)
 
   # returns the mac address from the collection of all address types
   def get_mac_address(addresses)

lib/ohai/plugins/linux/network.rb

@@ -702,7 +702,7 @@ def favored_default_route_linux(routes, iface, default_route, family)
     # Match the lead line for an interface from iproute2
     # 3: eth0.11@eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP
     # The '@eth0:' portion doesn't exist on primary interfaces and thus is optional in the regex
-    IPROUTE_INT_REGEX ||= /^(\d+): ([0-9a-zA-Z@:;\.\-_]*?)(@[0-9a-zA-Z\-_]+|):\s/.freeze
+    IPROUTE_INT_REGEX ||= /^(\d+): ([0-9a-zA-Z@:;\.\-_]*?)(@[0-9a-zA-Z\-_]+|):\s/
 
     if which("ip")
       # families to get default routes from

lib/ohai/plugins/rpm.rb

@@ -22,7 +22,7 @@
   provides "rpm"
   optional "true"
 
-  MACROS_MARKER = /========================/.freeze unless defined?(MACROS_MARKER)
+  MACROS_MARKER = /========================/ unless defined?(MACROS_MARKER)
 
   unless defined?(DO_NOT_SPLIT)
     DO_NOT_SPLIT = %w{

lib/ohai/plugins/windows/dmi.rb

@@ -37,7 +37,7 @@
   #
   # This cannot handle some property names, eg SMBIOSBIOSVersion.
   # https://rubular.com/r/FBNtXod4wkZGAG
-  SPLIT_REGEX ||= /[A-Z][a-z0-9]+|[A-Z]{2,}(?=[A-Z][a-z0-9])|[A-Z]{2,}/.freeze
+  SPLIT_REGEX ||= /[A-Z][a-z0-9]+|[A-Z]{2,}(?=[A-Z][a-z0-9])|[A-Z]{2,}/
 
   WINDOWS_TO_UNIX_KEYS ||= [
     %w{vendor manufacturer},

spec/functional/plugins/powershell_spec.rb

@@ -19,7 +19,7 @@
 require "spec_helper"
 
 describe Ohai::System, "languages plugin" do
-  VERSION_MATCHING_REGEX = /^(?:\d+\.)+\d+$/.freeze
+  VERSION_MATCHING_REGEX = /^(?:\d+\.)+\d+$/
   describe "powershell plugin", :windows_only do
     RSpec.shared_examples "a version looking thing" do
       it "is present" do