Remove toolVersion for jacoco and checkstyle

Remove versioning of Jacoco and Checkstyle. Instead they will be updated
by Gradle when it is updated. Dependabot does not update tool versions.
If issues come up, they can be corrected when Gradle is updated.

Author: benjamintboyle

build.gradle

@@ -18,8 +18,6 @@ ext {
     mockitoVersion = "3.9.0"
     jmhLibVersion = "1.21"
     guavaVersion = "30.1.1-jre"
-    jacocoVersion = "0.8.4"
-    checkstyleVersion = "8.41"
 }
 
 def releaseTag = System.getenv("BUILD_TAG")
@@ -164,10 +162,6 @@ task testng(type: Test) {
 
 check.dependsOn testng 
 
-jacoco {
-    toolVersion = jacocoVersion
-}
-
 jacocoTestReport {
     dependsOn test
     dependsOn testng
@@ -182,7 +176,6 @@ check.dependsOn jacocoTestReport
 
 checkstyle {
     configFile = rootProject.file("config/checkstyle/checkstyle.xml")
-    toolVersion = checkstyleVersion
     configProperties = [
             "checkstyle.suppressions.file": rootProject.file("config/checkstyle/suppressions.xml"),
             "checkstyle.header.file": rootProject.file("config/license/HEADER_JAVA")