Upgrade rubocop child dependencies (#931)

This specifically updates rexml to 3.3.7 from 3.2.5 which resolves a number of security vulnerabilities.

Gemfile.lock

@@ -9,7 +9,7 @@ GEM
       zeitwerk (~> 2.2, >= 2.2.2)
     addressable (2.7.0)
       public_suffix (>= 2.0.2, < 5.0)
-    ast (2.4.1)
+    ast (2.4.2)
     axiom-types (0.1.1)
       descendants_tracker (~> 0.0.4)
       ice_nine (~> 0.11.0)
@@ -218,9 +218,10 @@ GEM
       systemu (~> 2.6.4)
       wmi-lite (~> 1.0)
     paint (2.2.0)
-    parallel (1.19.2)
-    parser (2.7.2.0)
+    parallel (1.26.3)
+    parser (3.3.5.0)
       ast (~> 2.4.1)
+      racc
     pastel (0.8.0)
       tty-color (~> 0.5)
     plist (3.5.0)
@@ -229,14 +230,14 @@ GEM
     public_suffix (4.0.6)
     racc (1.7.3)
     rack (2.2.3)
-    rainbow (3.0.0)
+    rainbow (3.1.1)
     rake (13.2.1)
     rbnacl (4.0.2)
       ffi
     rbnacl-libsodium (1.0.16)
       rbnacl (>= 3.0.1)
     retryable (3.0.5)
-    rexml (3.2.5)
+    rexml (3.3.7)
     rspec (3.9.0)
       rspec-core (~> 3.9.0)
       rspec-expectations (~> 3.9.0)
@@ -264,7 +265,7 @@ GEM
       rexml
       ruby-progressbar (~> 1.7)
       unicode-display_width (>= 1.4.0, < 1.7)
-    ruby-progressbar (1.10.1)
+    ruby-progressbar (1.13.0)
     rubyntlm (0.6.2)
     rubyzip (2.3.0)
     rufus-lru (1.1.0)