⚡ Gradle build optimizations (#3670)

* ⚡ enable caching

* ⬆️ upgrade gradle to 6.6 in order to get access to metaInf runtime normalization functionality

* 🐛 fix failing test as a result of a minor change to gradle exception message when plugin cannot be applied

* ⚡ ignore Built-By and Built-Date attributes when examining the runtime classpath for changed values for task caching purposes

* 🔥 remove unneeded caching configuration

build.gradle

@@ -262,6 +262,14 @@ subprojects {
                  'Built-Gradle': gradle.gradleVersion
     }
   }
+  normalization {
+    runtimeClasspath {
+      metaInf {
+        ignoreAttribute("Built-By")
+        ignoreAttribute("Built-Date")
+      }
+    }
+  }
   /* JAR */
 
   /* MAVEN CENTRAL RELEASES */

gradle.properties

@@ -1 +1,2 @@
 org.gradle.jvmargs=-Xmx1024m
+org.gradle.caching=true

gradle/wrapper/gradle-wrapper.properties

@@ -1,5 +1,5 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-6.0.1-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-6.6.1-bin.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists

jib-gradle-plugin/src/test/java/com/google/cloud/tools/jib/gradle/JibPluginTest.java

@@ -137,7 +137,7 @@ public void testCheckJibVersionInvoked() {
     // Gradle tests aren't run from a jar and so don't have an identifiable plugin version
     assertThat(exception)
         .hasMessageThat()
-        .isEqualTo("Failed to apply plugin [id 'com.google.cloud.tools.jib']");
+        .isEqualTo("Failed to apply plugin 'com.google.cloud.tools.jib'.");
     assertThat(exception.getCause())
         .hasMessageThat()
         .isEqualTo("Could not determine Jib plugin version");