Set Java version with Gradle toolchain

Java version should be consistent for all tasks

"It has been possible to configure Gradle to build a project
with a different Java version than the one used to run Gradle. However,
it has required configuring each task like compilation, test, and javadoc separately.
Gradle 6.7 introduces “Java toolchain support”. In a nutshell,
it allows you to run Gradle with whatever version of Java you have installed,
while Gradle builds the project with the version of Java declared in a single place.
Gradle will automatically configure the build, detect already installed
JDKs and download the required JDK if it is not already installed."

More at https://blog.gradle.org/java-toolchains

Signed-off-by: Patryk Mis <foss@patrykmis.com>

app/build.gradle

@@ -39,6 +39,12 @@ project.ext {
     ]
 }
 
+java {
+    toolchain {
+        languageVersion.set(JavaLanguageVersion.of(11))
+    }
+}
+
 android {
     namespace 'com.aurora.store'
     compileSdk 33