JDK8 for TS plugin

only:proteus_f7

java_tools/build.gradle

@@ -11,6 +11,10 @@ allprojects {
           // TS still comes with 1.8 and we have a plugin, lets build compatible
           sourceCompatibility = '8'
           targetCompatibility = '8'
+          // [tag:java8]
+          toolchain {
+            languageVersion.set(JavaLanguageVersion.of(11))
+          }
         }
 
         dependencies {

java_tools/settings.gradle

@@ -1,3 +1,7 @@
+plugins {
+  // [tag:java8]
+  id 'org.gradle.toolchains.foojay-resolver-convention' version '0.8.0'
+}
 include ':trigger-image'
 include ':tune-tools'
 include ':proxy_server'