Update gradle wrapper

gradle/wrapper/gradle-wrapper.properties

-#
-# Testcontainers-CI
-# Copyright (c) 2021 Janne Mareike Koschinski
-#
-# This Source Code Form is subject to the terms of the Mozilla Public License,
-# v. 2.0. If a copy of the MPL was not distributed with this file, You can
-# obtain one at https://mozilla.org/MPL/2.0/.
-#
-
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-6.7-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-7.0.2-bin.zip
+distributionSha256Szm=0e46229820205440b48a5501122002842b82886e76af35f0f3a069243dca4b3c
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists