Build: Remove unnecessary build types release config for passcode lock

FYI: As part of the below PR#1678, the author most probably copy-pasted
an app module's 'build.gradle' configuration into this library module.
And with that, the author also copy-pasted this 'buildTypes.release'
related configuration by an oversight. 'PasscodeLock-Android' never had
such a configuration to begin with, and it being a library, it actually
didn't need it.

PasscodeLock-Android: https://github.com/wordpress-mobile/
PasscodeLock-Android
Related: [Lib] Migrate passcodelock directly into simplenote as a
library module. #1678
- #1678

PS: An alternative would have been to add a 'consumer-rules.pro' file to
have some extra ProGuard configuration for this library. But again,
'PasscodeLock-Android' never had such a need.

Author: ParaskP7

PasscodeLock/build.gradle

@@ -20,13 +20,6 @@ android {
         testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
     }
 
-    buildTypes {
-        release {
-            minifyEnabled true
-            shrinkResources false
-            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
-        }
-    }
     compileOptions {
         sourceCompatibility JavaVersion.VERSION_11
         targetCompatibility JavaVersion.VERSION_11