Use fixed kotlin version (1.3.50)

Author: Chrisvin

liquidswipe/build.gradle

@@ -47,7 +47,7 @@ android {
 
 dependencies {
     implementation fileTree(dir: 'libs', include: ['*.jar'])
-    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
+    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.3.50"
     implementation 'androidx.appcompat:appcompat:1.1.0'
     implementation 'androidx.core:core-ktx:1.1.0'
     implementation 'androidx.constraintlayout:constraintlayout:1.1.3'