docs: update REPL demo GIF with modern JS features

demo.tape

@@ -0,0 +1,30 @@
+Output docs/img/latestDemo.gif
+
+Set FontSize 20
+Set Width 1400
+Set Height 700
+Set TypingSpeed 100ms
+
+Type `./target/debug/boa`
+Enter
+Sleep 4s
+
+Type `2 + 2`
+Enter
+Sleep 3s
+
+Type `const greet = (name) => "Hello, " + name + "!"`
+Enter
+Sleep 3s
+
+Type `greet("World")`
+Enter
+Sleep 3s
+
+Type `[1, 2, 3].map(x => x * 2)`
+Enter
+Sleep 3s
+
+Type `try { null.property } catch(e) { console.log("Caught: " + e.message) }`
+Enter
+Sleep 4s