fix: increase default memory for Gradle builds on generated libraries (#907)

Author: chanseokoh

rules_java_gapic/BUILD.bazel

@@ -10,6 +10,7 @@ pkg_tar(
     files = {
         "resources/gradle/gradle/wrapper/gradle-wrapper.jar": "gradle/wrapper/gradle-wrapper.jar",
         "resources/gradle/gradle/wrapper/gradle-wrapper.properties": "gradle/wrapper/gradle-wrapper.properties",
+        "resources/gradle/gradle.properties": "gradle.properties",
         "resources/gradle/gradlew": "gradlew",
         "resources/gradle/gradlew.bat": "gradlew.bat",
     },

rules_java_gapic/resources/gradle/gradle.properties

@@ -0,0 +1 @@
+org.gradle.jvmargs=-Xmx2048m