Excavator: Apply Gradle Plugin Testing Helper (#1181)

Author: svc-excavator-bot

build.gradle

@@ -14,7 +14,7 @@ buildscript {
         classpath 'com.palantir.gradle.gitversion:gradle-git-version:3.1.0'
         classpath 'com.palantir.gradle.jdks:gradle-jdks:0.58.0'
         classpath 'com.palantir.gradle.jdkslatest:gradle-jdks-latest:0.16.0'
-        classpath 'com.palantir.gradle.plugintesting:gradle-plugin-testing:0.4.0'
+        classpath 'com.palantir.gradle.plugintesting:gradle-plugin-testing:0.5.0'
         classpath 'com.palantir.javaformat:gradle-palantir-java-format:2.50.0'
         classpath 'com.palantir.gradle.revapi:gradle-revapi:1.8.0'
         classpath 'com.palantir.javaformat:gradle-palantir-java-format:2.50.0'

versions.lock

@@ -64,7 +64,7 @@ com.google.guava:guava-testlib:27.0.1-jre (1 constraints: aa067c53)
 com.google.testing.compile:compile-testing:0.21.0 (1 constraints: 35052a3b)
 com.google.truth:truth:1.4.1 (2 constraints: 1f178e31)
 com.netflix.nebula:nebula-test:10.0.0 (1 constraints: 3305273b)
-com.palantir.gradle.plugintesting:plugin-testing-core:0.4.0 (1 constraints: 0605f735)
+com.palantir.gradle.plugintesting:plugin-testing-core:0.5.0 (1 constraints: 0705fa35)
 junit:junit:4.13.2 (7 constraints: da62ac41)
 net.bytebuddy:byte-buddy:1.14.11 (1 constraints: 7e0bc5ea)
 org.apiguardian:apiguardian-api:1.1.2 (7 constraints: 9d791b5f)