updated dependencies, cleanup request method

src/main/kotlin/com/becausesec/chuckjokes/controllers/JokeController.kt

@@ -5,6 +5,7 @@ import org.springframework.beans.factory.annotation.Autowired
 import org.springframework.stereotype.Controller
 import org.springframework.ui.Model
 import org.springframework.web.bind.annotation.RequestMapping
+import org.springframework.web.bind.annotation.RequestMethod
 
 @Controller
 class JokeController {
@@ -12,7 +13,7 @@ class JokeController {
     @Autowired
     lateinit var jokeService: JokeService
 
-    @RequestMapping(value=["/", ""])
+    @RequestMapping(value=["/", ""], method = [RequestMethod.GET])
     fun showJoke(model : Model) : String {
         model.addAttribute("joke", jokeService.joke)
         return "chucknorris"