Raise the limit in our toolchain conventions to 8

Author: niloc132

buildSrc/src/main/groovy/io.deephaven.java-toolchain-conventions.gradle

@@ -16,13 +16,13 @@ def testRuntimeVersion = Integer.parseInt((String)project.findProperty('testRunt
 def testRuntimeVendor = project.hasProperty('testRuntimeVendor') ?  JvmVendorSpec.matching((String)project.property('testRuntimeVendor')): null
 
 if (languageLevel > compilerVersion) {
-  throw new IllegalArgumentException("languageLevel must be less than or equal to compileVersion")
+  throw new IllegalArgumentException("languageLevel must be less than or equal to compilerVersion")
 }
-if (languageLevel < 8) {
-  throw new IllegalArgumentException("languageLevel must be greater than or equal to 8")
+if (languageLevel < 11) {
+  throw new IllegalArgumentException("languageLevel must be greater than or equal to 11")
 }
-if (testLanguageLevel < 8) {
-  throw new IllegalArgumentException("testLanguageLevel must be greater than or equal to 8")
+if (testLanguageLevel < 11) {
+  throw new IllegalArgumentException("testLanguageLevel must be greater than or equal to 11")
 }
 if (runtimeVersion < languageLevel) {
   throw new IllegalArgumentException("runtimeVersion must be greater than or equal to languageLevel")