Generics migration (#237)

* Generics migration

This attempts to migrate this library in the least invasive way by preserving as
much of the original API as possible. It does not change the tests in a
meaningful way nor does it attempt to upgrade any logic that can be simplified
or improved with generics. This is purely an API migration, and still requires a
lot of additional work to be fully ready.

* Fix a few broken tests around serialization

* Add v2 suffix

* Temporarily change mod name for testing

* Rename module to /v2

examples/arraystack/arraystack.go

@@ -4,20 +4,20 @@
 
 package main
 
-import "github.com/emirpasic/gods/stacks/arraystack"
+import "github.com/emirpasic/gods/v2/stacks/arraystack"
 
 // ArrayStackExample to demonstrate basic usage of ArrayStack
 func main() {
-	stack := arraystack.New() // empty
-	stack.Push(1)             // 1
-	stack.Push(2)             // 1, 2
-	stack.Values()            // 2, 1 (LIFO order)
-	_, _ = stack.Peek()       // 2,true
-	_, _ = stack.Pop()        // 2, true
-	_, _ = stack.Pop()        // 1, true
-	_, _ = stack.Pop()        // nil, false (nothing to pop)
-	stack.Push(1)             // 1
-	stack.Clear()             // empty
-	stack.Empty()             // true
-	stack.Size()              // 0
+	stack := arraystack.New[int]() // empty
+	stack.Push(1)                  // 1
+	stack.Push(2)                  // 1, 2
+	stack.Values()                 // 2, 1 (LIFO order)
+	_, _ = stack.Peek()            // 2,true
+	_, _ = stack.Pop()             // 2, true
+	_, _ = stack.Pop()             // 1, true
+	_, _ = stack.Pop()             // nil, false (nothing to pop)
+	stack.Push(1)                  // 1
+	stack.Clear()                  // empty
+	stack.Empty()                  // true
+	stack.Size()                   // 0
 }