Revert checkstyle version to 9.3 as 10.X.X requires a minimum of java 11

Author: jonathanaustin

build-tools/src/main/resources/bordertech/bt-checkstyle.xml

@@ -3,7 +3,7 @@
 		"-//Checkstyle//DTD Checkstyle Configuration 1.3//EN"
 		"https://checkstyle.org/dtds/configuration_1_3.dtd">
 
-<!-- Based on sun_checks.xml V10.7.0 (https://github.com/checkstyle/checkstyle/blob/checkstyle-10.7.0/src/main/resources/sun_checks.xml) -->
+<!-- Based on sun_checks.xml V9.3 (https://github.com/checkstyle/checkstyle/blob/checkstyle-9.3/src/main/resources/sun_checks.xml) -->
 
 <!--
 Checkstyle configuration that checks the sun coding conventions from:

qa-parent/pom.xml

@@ -90,7 +90,7 @@
 		<bt.jacoco.plugin.version>0.8.8</bt.jacoco.plugin.version>
 		<bt.surefire.plugin.version>2.22.2</bt.surefire.plugin.version>
 		<bt.checkstyle.plugin.version>3.2.1</bt.checkstyle.plugin.version>
-		<bt.checkstyle.version>10.7.0</bt.checkstyle.version>
+		<bt.checkstyle.version>9.3</bt.checkstyle.version>
 		<bt.pmd.plugin.version>3.20.0</bt.pmd.plugin.version>
 		<bt.pmd.version>6.54.0</bt.pmd.version>
 		<bt.spotbugs.plugin.version>4.7.3.0</bt.spotbugs.plugin.version>