[android] Update Gradle

To a version compatible with current Java, as well as with Volley

Author: valpackett

modules/openapi-generator/src/main/resources/android/gradle-wrapper.properties.mustache

@@ -1,5 +1,5 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-6.7.1-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-7.6.2-all.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists