fix: fix gradle version typo error

build.gradle

@@ -1,3 +1,19 @@
+/*
+ * Copyright 2019 namjug-kim
+ *
+ * LINE Corporation licenses this file to you under the Apache License,
+ * version 2.0 (the "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at:
+ *
+ *   https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ */
+
 apply plugin: 'java'
 
 group 'com.njkimg.reactive-crypto'
@@ -54,7 +70,7 @@ subprojects {
         implementation group: 'org.apache.commons', name: 'commons-lang3', version: '3.9'
 
         // reactor
-        implementation group: 'io.projectreactor', name: 'reactor-core', version: '${reactorVersion}'
+        implementation group: 'io.projectreactor', name: 'reactor-core', version: "${reactorVersion}"
         implementation group: 'org.jetbrains.kotlin', name: 'kotlin-stdlib', version: '1.3.40'
 
         // logging
@@ -64,7 +80,7 @@ subprojects {
         // test
         testCompile group: 'junit', name: 'junit', version: '4.12'
         testCompile group: 'org.assertj', name: 'assertj-core', version: '3.12.2'
-        testCompile group: 'io.projectreactor', name: 'reactor-test', version: reactorVersion
+        testCompile group: 'io.projectreactor', name: 'reactor-test', version: "${reactorVersion}"
 
         testRuntimeOnly group: 'org.apache.logging.log4j', name: 'log4j-api', version: "${log4j2Version}"
         testRuntimeOnly group: 'org.apache.logging.log4j', name: 'log4j-core', version: "${log4j2Version}"
@@ -107,4 +123,4 @@ task codeCoverageReport(type: JacocoReport) {
 
 codeCoverageReport.dependsOn {
     subprojects*.test
-}
+}