Fixed deprecation warnings

Author: cc-jhr

core/src/test/kotlin/de/codecentric/hikaku/extensions/FileExtensionsTest.kt

@@ -3,6 +3,7 @@ package de.codecentric.hikaku.extensions
 import org.junit.jupiter.api.Nested
 import org.junit.jupiter.api.Test
 import java.io.File
+import kotlin.io.path.createTempDirectory
 import kotlin.test.assertFailsWith
 
 class FileExtensionsTest {
@@ -20,7 +21,7 @@ class FileExtensionsTest {
         @Test
         fun `directory in validity check throws an exception`() {
             assertFailsWith<IllegalArgumentException> {
-                createTempDir().checkFileValidity()
+                createTempDirectory().checkFileValidity()
             }
         }
 

raml/src/main/kotlin/de/codecentric/hikaku/converters/raml/extensions/MethodExtensions.kt

@@ -5,7 +5,7 @@ import de.codecentric.hikaku.endpoints.HttpMethod
 import de.codecentric.hikaku.endpoints.QueryParameter
 import org.raml.v2.api.model.v10.methods.Method
 
-internal fun Method.hikakuHttpMethod() = HttpMethod.valueOf(this.method().toUpperCase())
+internal fun Method.hikakuHttpMethod() = HttpMethod.valueOf(this.method().uppercase())
 
 internal fun Method.hikakuQueryParameters(): Set<QueryParameter> {
     return this.queryParameters()