ktor: upgrade ktor to 0.9.1 (#3218)

frameworks/Kotlin/ktor/pom.xml

@@ -16,7 +16,7 @@
         <gson.version>2.8.2</gson.version>
         <hikaricp.version>2.7.4</hikaricp.version>
         <kotlin.version>1.2.21</kotlin.version>
-        <ktor.version>0.9.1-alpha-10</ktor.version>
+        <ktor.version>0.9.1</ktor.version>
         <logback.version>1.2.3</logback.version>
         <mysql-connector.version>5.1.44</mysql-connector.version>
     </properties>