Upgrade Checkstyle version to 10.18.2

Merge request !1123 (merged) has a build error on Checkstyle:

com.puppycrawl.tools.checkstyle.api.CheckstyleException: Exception was thrown while processing [...]\git\escet\cif\org.eclipse.escet.cif.simulator\src\org\eclipse\escet\cif\simulator\compiler\AssignmentCodeGenerator.java
	at com.puppycrawl.tools.checkstyle.Checker.processFiles(Checker.java:302)
	at com.puppycrawl.tools.checkstyle.Checker.process(Checker.java:221)
	at net.sf.eclipsecs.core.builder.Auditor.runAudit(Auditor.java:146)
	at net.sf.eclipsecs.core.builder.CheckstyleBuilder.handleBuildSelection(CheckstyleBuilder.java:307)
	at net.sf.eclipsecs.core.builder.CheckstyleBuilder.build(CheckstyleBuilder.java:173)
        ...
Caused by: com.puppycrawl.tools.checkstyle.api.CheckstyleException: IllegalStateException occurred while parsing file [...]\git\escet\cif\org.eclipse.escet.cif.simulator\src\org\eclipse\escet\cif\simulator\compiler\AssignmentCodeGenerator.java.
	at com.puppycrawl.tools.checkstyle.JavaParser.parse(JavaParser.java:120)
	at com.puppycrawl.tools.checkstyle.TreeWalker.processFiltered(TreeWalker.java:152)
	at com.puppycrawl.tools.checkstyle.api.AbstractFileSetCheck.process(AbstractFileSetCheck.java:87)
	at com.puppycrawl.tools.checkstyle.Checker.processFile(Checker.java:328)
	at com.puppycrawl.tools.checkstyle.Checker.processFiles(Checker.java:289)
	... 17 more
Caused by: java.lang.IllegalStateException: [...]\git\escet\cif\org.eclipse.escet.cif.simulator\src\org\eclipse\escet\cif\simulator\compiler\AssignmentCodeGenerator.java:639:24: unexpected token: name
	at com.puppycrawl.tools.checkstyle.JavaParser$1.reportError(JavaParser.java:108)
	at com.puppycrawl.tools.checkstyle.grammar.GeneratedJavaRecognizer.typeDefinition(GeneratedJavaRecognizer.java:424)
	at com.puppycrawl.tools.checkstyle.grammar.GeneratedJavaRecognizer.compilationUnit(GeneratedJavaRecognizer.java:212)
	at com.puppycrawl.tools.checkstyle.JavaParser.parse(JavaParser.java:114)
	... 21 more
Caused by: [...]\git\escet\cif\org.eclipse.escet.cif.simulator\src\org\eclipse\escet\cif\simulator\compiler\AssignmentCodeGenerator.java:639:24: unexpected token: name
	at com.puppycrawl.tools.checkstyle.grammar.GeneratedJavaRecognizer.traditionalStatement(GeneratedJavaRecognizer.java:6057)
	at com.puppycrawl.tools.checkstyle.grammar.GeneratedJavaRecognizer.statement(GeneratedJavaRecognizer.java:4815)
	at com.puppycrawl.tools.checkstyle.grammar.GeneratedJavaRecognizer.compoundStatement(GeneratedJavaRecognizer.java:4544)
        ...

It can't handle certain syntax of newer Java versions, it seems.

We currently use:

In the development environment: Eclipse Checkstyle 8.41.1.202105102159, which uses Checkstyle 8.41.
In the build: Maven Checkstyle Plugin 3.1.2, configured to explicitly use Checkstyle 8.41.