Support diffing Kotlin metadata versions for classes

[Goooler]

OLD: old.jar
NEW: new.jar

       │         compressed         │        uncompressed         
       ├──────────┬─────────┬───────┼──────────┬──────────┬───────
 JAR   │ old      │ new     │ diff  │ old      │ new      │ diff  
───────┼──────────┼─────────┼───────┼──────────┼──────────┼───────
 class │    876 B │   883 B │  +7 B │ 1.24 KiB │ 1.26 KiB │ +12 B 
 other │    628 B │   653 B │ +25 B │     72 B │     72 B │   0 B 
───────┼──────────┼─────────┼───────┼──────────┼──────────┼───────
 total │ 1.47 KiB │ 1.5 KiB │ +32 B │ 1.31 KiB │ 1.33 KiB │ +12 B 

 CLASSES │ old │ new │ diff      
─────────┼─────┼─────┼───────────
 classes │   1 │   1 │ 0 (+0 -0) 
 methods │   5 │   5 │ 0 (+1 -1) 
  fields │   1 │   1 │ 0 (+0 -0) 

=================
====   JAR   ====
=================

    compressed     │   uncompressed   │                                               
──────────┬────────┼──────────┬───────┤                                               
 size     │ diff   │ size     │ diff  │ path                                          
──────────┼────────┼──────────┼───────┼───────────────────────────────────────────────
    204 B │ +204 B │     47 B │ +47 B │ + META-INF/org.example_untitled.kotlin_module 
          │ -179 B │          │ -47 B │ - META-INF/untitled.kotlin_module             
    883 B │   +7 B │ 1.26 KiB │ +12 B │ ∆ org/example/MainKt.class                    
──────────┼────────┼──────────┼───────┼───────────────────────────────────────────────
 1.06 KiB │  +32 B │  1.3 KiB │ +12 B │ (total)                                       


=====================
====   CLASSES   ====
=====================

BYTECODE VERSIONS:

   old │ new │ diff      
  ─────┼─────┼───────────
   1   │ 1   │ 0 (+1 -1) 
  
  + org.example.MainKt: 65
  
  - org.example.MainKt: 69
  

KOTLIN METADATA VERSIONS:

   old │ new │ diff      
  ─────┼─────┼───────────
   1   │ 1   │ 0 (+1 -1) 
  
  + org.example.MainKt: 2.4.0
  
  - org.example.MainKt: 2.3.0
  

METHODS:

   old │ new │ diff      
  ─────┼─────┼───────────
   5   │ 5   │ 0 (+1 -1) 
  
  + org.example.MainKt main3()
  
  - org.example.MainKt main2()

Closes #541.

[Goooler]

I'll probably prettify the outputs in #491.